feat: remember inferred location in unifyPair

independentTest.sh

@@ -10,6 +10,7 @@ mkdir $TDIR
 cd $TDIR
 git clone $REPO .
 git checkout feat/unify-server
+# git checkout 93e1a8787cd94c73f4538f6a348f58613893a584
 # git checkout dad468368b86bdd5a3d3b2754b17617cee0a9107 # 1:55
 # git checkout a0c11b60e8c9d7addcbe0d3a09c9ce2924e9d5c0 # 2:25
 # git checkout 4cddf73e6d6c9116d3e1705c4b27a8e7f18d80c3 # 2:27
@@ -19,15 +20,14 @@ git checkout feat/unify-server
 # git checkout 1391206dfe59263cdb22f93371cfd1dd5465d97f # 1:29
 
 date "+%Y.%m.%d %H:%M:%S"
-
-# mvn clean compile -DskipTests package
-## prefix each stderr line with " | "
-# exec 2> >(trap "" INT TERM; sed 's/^/ | /' >&2)
-# echo -e "\nMatrix test:\n |"
-# time java -jar target/JavaTXcompiler-0.1-jar-with-dependencies.jar resources/bytecode/javFiles/Matrix.jav >/dev/null;
+# sed -i -e 's/source>21/source>23/g' pom.xml
+# sed -i -e 's/target>21/target>23/g' pom.xml
 
 
-mvn clean compile test
+mvn clean compile -DskipTests package
+time java -jar target/JavaTXcompiler-0.1-jar-with-dependencies.jar resources/bytecode/javFiles/Matrix.jav;
+
+# mvn clean compile test
 
 
 echo -e "\nCleanup... "

pom.xml

@@ -59,6 +59,11 @@ http://maven.apache.org/maven-v4_0_0.xsd">
 			<artifactId>jackson-databind</artifactId>
 			<version>2.17.2</version>
 		</dependency>
+		<dependency>
+			<groupId>com.diogonunes</groupId>
+			<artifactId>JColor</artifactId>
+			<version>5.5.1</version>
+		</dependency>
 	</dependencies>
 
 	<build>

src/main/java/de/dhbwstuttgart/bytecode/Codegen.java

@@ -8,6 +8,7 @@ import de.dhbwstuttgart.target.generate.ASTToTargetAST;
 import de.dhbwstuttgart.target.tree.*;
 import de.dhbwstuttgart.target.tree.expression.*;
 import de.dhbwstuttgart.target.tree.type.*;
+import de.dhbwstuttgart.util.Logger;
 import org.objectweb.asm.*;
 
 import java.lang.invoke.*;
@@ -19,6 +20,8 @@ import static de.dhbwstuttgart.target.tree.expression.TargetBinaryOp.*;
 import static de.dhbwstuttgart.target.tree.expression.TargetLiteral.*;
 
 public class Codegen {
+    public static Logger logger = new Logger("codegen");
+
     private final TargetStructure clazz;
     private final ClassWriter cw;
     public final String className;
@@ -1317,7 +1320,7 @@ public class Codegen {
                 types.add(Type.getObjectType(guard.inner().type().getInternalName()));
                 // TODO Same here we need to evaluate constant;
             } else {
-                System.out.println(label);
+                logger.info(label);
                 throw new NotImplementedException();
             }
         }

src/main/java/de/dhbwstuttgart/bytecode/FunNGenerator.java

@@ -120,7 +120,7 @@ public class FunNGenerator {
             superFunNMethodDescriptor.append(")V");
         }
 
-        System.out.println(superFunNMethodSignature);
+        Codegen.logger.info(superFunNMethodSignature);
 
         ClassWriter classWriter = new ClassWriter(0);
         MethodVisitor methodVisitor;

src/main/java/de/dhbwstuttgart/core/ConsoleInterface.java

@@ -1,13 +1,19 @@
 package de.dhbwstuttgart.core;
 
+import de.dhbwstuttgart.server.SocketClient;
+import de.dhbwstuttgart.util.Logger;
 import java.io.File;
 import java.io.IOException;
-import java.io.OutputStream;
-import java.io.PrintStream;
 import java.util.*;
 
 public class ConsoleInterface {
-  private static final String directory = System.getProperty("user.dir");
+
+  /**
+   * Leave the argument configurations here for the rest of the code to read
+   */
+  public static Logger.LogLevel logLevel = Logger.LogLevel.ERROR;
+  public static boolean writeLogFiles = false;
+  public static Optional<String> unifyServerUrl = Optional.empty();
 
   public static void main(String[] args) throws IOException, ClassNotFoundException {
     List<File> input = new ArrayList<>();
@@ -15,7 +21,6 @@ public class ConsoleInterface {
     String outputPath = null;
     Iterator<String> it = Arrays.asList(args).iterator();
     Optional<Integer> serverPort = Optional.empty();
-    Optional<String> unifyServer = Optional.empty();
 
     if (args.length == 0) {
       System.out.println("No input files given. Get help with --help");
@@ -25,7 +30,9 @@ public class ConsoleInterface {
         "\t-cp\tSet Classpath\n" +
         "\t-d\tSet destination directory\n" +
         "\t[--server-mode <port>]\n" +
-        "\t[--unify-server <url>]\n");
+        "\t[--unify-server <url>]\n" +
+        "\t[--write-logs]\n" +
+        "\t[-v|-vv-|-vvv]");
       System.exit(1);
     }
     while (it.hasNext()) {
@@ -42,22 +49,31 @@ public class ConsoleInterface {
       } else if (arg.equals("--server-mode")) {
         serverPort = Optional.of(Integer.parseInt(it.next()));
       } else if (arg.equals("--unify-server")) {
-        unifyServer = Optional.of(it.next());
+        unifyServerUrl = Optional.of(it.next());
+      } else if (arg.equals("--write-logs")) {
+        ConsoleInterface.writeLogFiles = true;
+      } else if (arg.startsWith("-v")) {
+        logLevel = switch (arg) {
+          case "-v" -> Logger.LogLevel.WARNING;
+          case "-vv" -> Logger.LogLevel.INFO;
+          case "-vvv" -> Logger.LogLevel.DEBUG;
+          default -> throw new IllegalArgumentException("Argument " + arg + " is not a valid verbosity level");
+        };
       } else {
         input.add(new File(arg));
       }
     }
 
     if (serverPort.isPresent()) {
-      if (unifyServer.isPresent()) throw new RuntimeException("Cannot use unifyServer when in server mode!");
-
-      JavaTXServer server = new JavaTXServer();
-      server.listen(serverPort.get());
+      if (unifyServerUrl.isPresent()) throw new RuntimeException("Cannot use unifyServer when in server mode!");
+      JavaTXServer server = new JavaTXServer(serverPort.get());
+      server.listen();
     }
     else {
-      JavaTXCompiler compiler = new JavaTXCompiler(input, classpath, outputPath != null ? new File(outputPath) : null, unifyServer);
+      JavaTXCompiler compiler = new JavaTXCompiler(input, classpath, outputPath != null ? new File(outputPath) : null);
       //compiler.typeInference();
       compiler.generateBytecode();
+      SocketClient.closeIfOpen();
     }
   }
 

src/main/java/de/dhbwstuttgart/core/JavaTXCompiler.java

@@ -13,6 +13,10 @@ import de.dhbwstuttgart.parser.antlr.Java17Parser.SourceFileContext;
 import de.dhbwstuttgart.parser.scope.JavaClassName;
 import de.dhbwstuttgart.parser.scope.JavaClassRegistry;
 import de.dhbwstuttgart.server.SocketClient;
+import de.dhbwstuttgart.server.SocketFuture;
+import de.dhbwstuttgart.server.packet.SetAutoclosePacket;
+import de.dhbwstuttgart.server.packet.UnifyRequestPacket;
+import de.dhbwstuttgart.server.packet.UnifyResultPacket;
 import de.dhbwstuttgart.syntaxtree.ClassOrInterface;
 import de.dhbwstuttgart.syntaxtree.GenericTypeVar;
 import de.dhbwstuttgart.syntaxtree.Method;
@@ -53,6 +57,7 @@ import de.dhbwstuttgart.typeinference.unify.UnifyResultListenerImpl;
 import de.dhbwstuttgart.typeinference.unify.UnifyResultModel;
 import de.dhbwstuttgart.typeinference.unify.UnifyTaskModel;
 
+import de.dhbwstuttgart.util.Logger;
 import java.io.*;
 import java.lang.reflect.Modifier;
 import java.nio.file.Path;
@@ -65,43 +70,37 @@ import org.apache.commons.io.output.NullOutputStream;
 
 public class JavaTXCompiler {
 
+	// do not use this in any code, that can be executed serverside!
+	public static PlaceholderRegistry defaultClientPlaceholderRegistry = new PlaceholderRegistry();
+	public static Logger defaultLogger = new Logger();
+
 	// public static JavaTXCompiler INSTANCE;
 	final CompilationEnvironment environment;
 	Boolean resultmodel = true;
 	public final Map<File, SourceFile> sourceFiles = new HashMap<>();
 
-	Boolean log = false; //gibt an ob ein Log-File nach System.getProperty("user.dir")+""/logFiles/"" geschrieben werden soll?
 	public volatile UnifyTaskModel usedTasks = new UnifyTaskModel();
 	public final DirectoryClassLoader classLoader;
 
 	public final List<File> classPath;
 	private final File outputPath;
 
-	private final Optional<String> unifyServer;
-
 	public DirectoryClassLoader getClassLoader() {
 		return classLoader;
 	}
 
 	public JavaTXCompiler(File sourceFile) throws IOException, ClassNotFoundException {
-		this(Arrays.asList(sourceFile), List.of(), new File("."), Optional.empty());
-	}
-
-	public JavaTXCompiler(File sourceFile, Boolean log) throws IOException, ClassNotFoundException {
-		this(sourceFile);
-		this.log = log;
+		this(Collections.singletonList(sourceFile), List.of(), new File("."));
 	}
 
 	public JavaTXCompiler(List<File> sourceFiles) throws IOException, ClassNotFoundException {
-		this(sourceFiles, List.of(), new File("."), Optional.empty());
+		this(sourceFiles, List.of(), new File("."));
 	}
 
 	public JavaTXCompiler(List<File> sources, List<File> contextPath, File outputPath) throws IOException, ClassNotFoundException {
-		this(sources, contextPath, outputPath, Optional.empty());
-	}
+		// ensure new default placeholder registry for tests
+		defaultClientPlaceholderRegistry = new PlaceholderRegistry();
 
-	public JavaTXCompiler(List<File> sources, List<File> contextPath, File outputPath, Optional<String> unifyServer) throws IOException, ClassNotFoundException {
-		this.unifyServer = unifyServer;
 		var path = new ArrayList<>(contextPath);
 		if (contextPath.isEmpty()) {
 			// When no contextPaths are given, the working directory is the sources root
@@ -311,52 +310,51 @@ public class JavaTXCompiler {
 		Set<Set<UnifyPair>> results = new HashSet<>();
 		UnifyResultModel urm = null;
 		// urm.addUnifyResultListener(resultListener);
-		UnifyContext context = new UnifyContext(logFile, log, true, urm, usedTasks, PlaceholderRegistry.defaultRegistry);
-		try {
-			logFile = logFile == null ? new FileWriter(new File("log_" + sourceFiles.keySet().iterator().next().getName())) : logFile;
-			IFiniteClosure finiteClosure = UnifyTypeFactory.generateFC(allClasses, logFile, getClassLoader(), this, context.placeholderRegistry());
-			System.out.println(finiteClosure);
-			urm = new UnifyResultModel(cons, finiteClosure);
-			urm.addUnifyResultListener(resultListener);
-			ConstraintSet<UnifyPair> unifyCons = UnifyTypeFactory.convert(this, cons, context.placeholderRegistry());
+		logFile = logFile == null ? new FileWriter("log_" + sourceFiles.keySet().iterator().next().getName()) : logFile;
+		Logger logger = new Logger(logFile, "TypeInferenceAsync");
+		UnifyContext context = new UnifyContext(logger, true, urm, usedTasks, defaultClientPlaceholderRegistry);
 
-			Function<UnifyPair, UnifyPair> distributeInnerVars = x -> {
-				UnifyType lhs, rhs;
-				if (((lhs = x.getLhsType()) instanceof PlaceholderType) && ((rhs = x.getRhsType()) instanceof PlaceholderType) && (((PlaceholderType) lhs).isInnerType() || ((PlaceholderType) rhs).isInnerType())) {
-					((PlaceholderType) lhs).setInnerType(true);
-					((PlaceholderType) rhs).setInnerType(true);
-				}
-				return x;
+		IFiniteClosure finiteClosure = UnifyTypeFactory.generateFC(allClasses, logger, getClassLoader(), this, context.placeholderRegistry());
+		logger.info(finiteClosure.toString());
+		urm = new UnifyResultModel(cons, finiteClosure);
+		urm.addUnifyResultListener(resultListener);
+		ConstraintSet<UnifyPair> unifyCons = UnifyTypeFactory.convert(this, cons, context.placeholderRegistry());
 
-			};
-			logFile.write(unifyCons.toString());
-			unifyCons = unifyCons.map(distributeInnerVars);
-			logFile.write(unifyCons.toString());
-			// Set<Set<UnifyPair>> results = new HashSet<>(); Nach vorne gezogen
-			logFile.write("FC:\\" + finiteClosure.toString() + "\n");
-			for (SourceFile f : this.sourceFiles.values()) {
-				logFile.write(ASTTypePrinter.print(f));
+		Function<UnifyPair, UnifyPair> distributeInnerVars = x -> {
+			UnifyType lhs, rhs;
+			if (((lhs = x.getLhsType()) instanceof PlaceholderType) && ((rhs = x.getRhsType()) instanceof PlaceholderType) && (((PlaceholderType) lhs).isInnerType() || ((PlaceholderType) rhs).isInnerType())) {
+				((PlaceholderType) lhs).setInnerType(true);
+				((PlaceholderType) rhs).setInnerType(true);
 			}
-			// logFile.flush();
-			Set<PlaceholderType> varianceTPHold;
-			Set<PlaceholderType> varianceTPH = new HashSet<>();
-			varianceTPH = varianceInheritanceConstraintSet(unifyCons);
+			return x;
 
-			/*
-			 * PL 2018-11-07 wird in varianceInheritanceConstraintSet erledigt do { //PL 2018-11-05 Huellenbildung Variance auf alle TPHs der Terme auf der jeweiligen //anderen Seite übertragen varianceTPHold = new HashSet<>(varianceTPH); varianceTPH = varianceInheritanceConstraintSet(unifyCons); unifyCons.map( y -> { if ((y.getLhsType() instanceof PlaceholderType) && (y.getRhsType() instanceof PlaceholderType)) { if (((PlaceholderType)y.getLhsType()).getVariance() != 0 &&
-			 * ((PlaceholderType)y.getRhsType()).getVariance() == 0) { ((PlaceholderType)y.getRhsType()).setVariance(((PlaceholderType)y.getLhsType( )).getVariance()); } if (((PlaceholderType)y.getLhsType()).getVariance() == 0 && ((PlaceholderType)y.getRhsType()).getVariance() != 0) { ((PlaceholderType)y.getLhsType()).setVariance(((PlaceholderType)y.getRhsType( )).getVariance()); } } return y; } ); } while (!varianceTPHold.equals(varianceTPH));
-			 */
-
-			// Set<Set<UnifyPair>> result = unify.unifySequential(xConsSet, finiteClosure,
-			// logFile, log);
-			// Set<Set<UnifyPair>> result = unify.unify(xConsSet, finiteClosure);
-			List<Set<Constraint<UnifyPair>>> oderConstraints = unifyCons.getOderConstraints()/*
-																								 * .stream().map(x -> { Set<Set<UnifyPair>> ret = new HashSet<>(); for (Constraint<UnifyPair> y : x) { ret.add(new HashSet<>(y)); } return ret; }).collect(Collectors. toCollection(ArrayList::new))
-																								 */;
-			TypeUnify.unifyAsync(unifyCons.getUndConstraints(), oderConstraints, finiteClosure, context);
-		} catch (IOException e) {
-			System.err.println("kein LogFile");
+		};
+		logger.debug(unifyCons.toString());
+		unifyCons = unifyCons.map(distributeInnerVars);
+		logger.debug(unifyCons.toString());
+		// Set<Set<UnifyPair>> results = new HashSet<>(); Nach vorne gezogen
+		logger.debug("FC:\\" + finiteClosure.toString() + "\n");
+		for (SourceFile f : this.sourceFiles.values()) {
+			logger.debug(ASTTypePrinter.print(f));
 		}
+		// logFile.flush();
+		Set<PlaceholderType> varianceTPHold;
+		Set<PlaceholderType> varianceTPH = new HashSet<>();
+		varianceTPH = varianceInheritanceConstraintSet(unifyCons);
+
+		/*
+		 * PL 2018-11-07 wird in varianceInheritanceConstraintSet erledigt do { //PL 2018-11-05 Huellenbildung Variance auf alle TPHs der Terme auf der jeweiligen //anderen Seite übertragen varianceTPHold = new HashSet<>(varianceTPH); varianceTPH = varianceInheritanceConstraintSet(unifyCons); unifyCons.map( y -> { if ((y.getLhsType() instanceof PlaceholderType) && (y.getRhsType() instanceof PlaceholderType)) { if (((PlaceholderType)y.getLhsType()).getVariance() != 0 &&
+		 * ((PlaceholderType)y.getRhsType()).getVariance() == 0) { ((PlaceholderType)y.getRhsType()).setVariance(((PlaceholderType)y.getLhsType( )).getVariance()); } if (((PlaceholderType)y.getLhsType()).getVariance() == 0 && ((PlaceholderType)y.getRhsType()).getVariance() != 0) { ((PlaceholderType)y.getLhsType()).setVariance(((PlaceholderType)y.getRhsType( )).getVariance()); } } return y; } ); } while (!varianceTPHold.equals(varianceTPH));
+		 */
+
+		// Set<Set<UnifyPair>> result = unify.unifySequential(xConsSet, finiteClosure,
+		// logFile, log);
+		// Set<Set<UnifyPair>> result = unify.unify(xConsSet, finiteClosure);
+		List<Set<Constraint<UnifyPair>>> oderConstraints = unifyCons.getOderConstraints()/*
+																							 * .stream().map(x -> { Set<Set<UnifyPair>> ret = new HashSet<>(); for (Constraint<UnifyPair> y : x) { ret.add(new HashSet<>(y)); } return ret; }).collect(Collectors. toCollection(ArrayList::new))
+																							 */;
+		TypeUnify.unifyAsync(unifyCons.getUndConstraints(), oderConstraints, finiteClosure, context);
+
 		return urm;
 	}
 
@@ -377,103 +375,106 @@ public class JavaTXCompiler {
 		final ConstraintSet<Pair> cons = getConstraints(file);
 		Set<Set<UnifyPair>> results = new HashSet<>();
 		PlaceholderRegistry placeholderRegistry = new PlaceholderRegistry();
-		try {
-			var logFolder = new File(System.getProperty("user.dir") + "/logFiles/");
-			if (log) logFolder.mkdirs();
-			Writer logFile = log ? new FileWriter(new File(logFolder, "log_" + sourceFiles.keySet().iterator().next().getName())) : new OutputStreamWriter(new NullOutputStream());
-			FiniteClosure finiteClosure = UnifyTypeFactory.generateFC(allClasses.stream().toList(), logFile, classLoader, this, placeholderRegistry);
-			System.out.println(finiteClosure);
-			ConstraintSet<UnifyPair> unifyCons = UnifyTypeFactory.convert(this, cons, placeholderRegistry);
-			System.out.println("xxx1");
-			Function<UnifyPair, UnifyPair> distributeInnerVars = x -> {
-				UnifyType lhs, rhs;
-				if (((lhs = x.getLhsType()) instanceof PlaceholderType) && ((rhs = x.getRhsType()) instanceof PlaceholderType) && (((PlaceholderType) lhs).isInnerType() || ((PlaceholderType) rhs).isInnerType())) {
-					((PlaceholderType) lhs).setInnerType(true);
-					((PlaceholderType) rhs).setInnerType(true);
-				}
-				return x;
 
-			};
+		var logFolder = new File(System.getProperty("user.dir") + "/logFiles/");
+		if (ConsoleInterface.writeLogFiles && !logFolder.mkdirs()) throw new RuntimeException("Could not creat directoy for log files: " + logFolder);
+		Writer logFile = ConsoleInterface.writeLogFiles ? new FileWriter(new File(logFolder, "log_" + sourceFiles.keySet().iterator().next().getName())) : new OutputStreamWriter(new NullOutputStream());
+		Logger logger = new Logger(logFile, "TypeInference");
 
-			logFile.write("Unify:" + unifyCons.toString());
-			System.out.println("Unify:" + unifyCons.toString());
-			unifyCons = unifyCons.map(distributeInnerVars);
-			logFile.write("\nUnify_distributeInnerVars: " + unifyCons.toString());
-			// Set<Set<UnifyPair>> results = new HashSet<>(); Nach vorne gezogen
-			logFile.write("FC:\\" + finiteClosure.toString() + "\n");
-			logFile.write(ASTTypePrinter.print(sf));
-			System.out.println(ASTTypePrinter.print(sf));
-			// logFile.flush();
-			System.out.println("Unify nach Oder-Constraints-Anpassung:" + unifyCons.toString());
-			Set<PlaceholderType> varianceTPHold;
-			Set<PlaceholderType> varianceTPH = new HashSet<>();
-			varianceTPH = varianceInheritanceConstraintSet(unifyCons);
-
-			/*
-			 * PL 2018-11-07 wird in varianceInheritanceConstraintSet erledigt do { //PL 2018-11-05 Huellenbildung Variance auf alle TPHs der Terme auf der jeweiligen //anderen Seite übertragen varianceTPHold = new HashSet<>(varianceTPH); varianceTPH = varianceInheritanceConstraintSet(unifyCons); unifyCons.map( y -> { if ((y.getLhsType() instanceof PlaceholderType) && (y.getRhsType() instanceof PlaceholderType)) { if (((PlaceholderType)y.getLhsType()).getVariance() != 0 &&
-			 * ((PlaceholderType)y.getRhsType()).getVariance() == 0) { ((PlaceholderType)y.getRhsType()).setVariance(((PlaceholderType)y.getLhsType( )).getVariance()); } if (((PlaceholderType)y.getLhsType()).getVariance() == 0 && ((PlaceholderType)y.getRhsType()).getVariance() != 0) { ((PlaceholderType)y.getLhsType()).setVariance(((PlaceholderType)y.getRhsType( )).getVariance()); } } return y; } ); } while (!varianceTPHold.equals(varianceTPH));
-			 */
-
-			// Set<Set<UnifyPair>> result = unify.unifySequential(xConsSet, finiteClosure,
-			// logFile, log);
-			// Set<Set<UnifyPair>> result = unify.unify(xConsSet, finiteClosure);
-			List<Set<Constraint<UnifyPair>>> oderConstraints = unifyCons.getOderConstraints()// .stream().map(x -> {
-			/*
-			 * Set<Set<UnifyPair>> ret = new HashSet<>(); for (Constraint<UnifyPair> y : x) { ret.add(new HashSet<>(y)); } return ret; }).collect(Collectors.toCollection(ArrayList::new))
-			 */;
-
-		  if (unifyServer.isPresent()) {
-				UnifyResultModel urm = new UnifyResultModel(cons, finiteClosure);
-				UnifyContext context = new UnifyContext(logFile, log, true, urm, usedTasks, placeholderRegistry);
-				SocketClient socketClient = new SocketClient(unifyServer.get());
-				return socketClient.execute(finiteClosure, cons, unifyCons, context);
-		  }
-			else if (resultmodel) {
-				/* UnifyResultModel Anfang */
-				UnifyResultModel urm = new UnifyResultModel(cons, finiteClosure);
-				UnifyResultListenerImpl li = new UnifyResultListenerImpl();
-				urm.addUnifyResultListener(li);
-				UnifyContext context = new UnifyContext(logFile, log, true, urm, usedTasks, placeholderRegistry);
-				TypeUnify.unifyParallel(unifyCons.getUndConstraints(), oderConstraints, finiteClosure, context);
-				System.out.println("RESULT Final: " + li.getResults());
-				System.out.println("Constraints for Generated Generics: " + " ???");
-				logFile.write("RES_FINAL: " + li.getResults().toString() + "\n");
-				// logFile.flush();
-				return li.getResults();
+		FiniteClosure finiteClosure = UnifyTypeFactory.generateFC(allClasses.stream().toList(), logger, classLoader, this, placeholderRegistry);
+		logger.info(finiteClosure.toString());
+		ConstraintSet<UnifyPair> unifyCons = UnifyTypeFactory.convert(this, cons, placeholderRegistry);
+		logger.info("xxx1");
+		Function<UnifyPair, UnifyPair> distributeInnerVars = x -> {
+			UnifyType lhs, rhs;
+			if (((lhs = x.getLhsType()) instanceof PlaceholderType) && ((rhs = x.getRhsType()) instanceof PlaceholderType) && (((PlaceholderType) lhs).isInnerType() || ((PlaceholderType) rhs).isInnerType())) {
+				((PlaceholderType) lhs).setInnerType(true);
+				((PlaceholderType) rhs).setInnerType(true);
 			}
-			/* UnifyResultModel End */
-			else {
-				// Set<Set<UnifyPair>> result = unify.unify(unifyCons.getUndConstraints(),
-				// oderConstraints, finiteClosure, logFile, log, new UnifyResultModel(cons,
-				// finiteClosure));
-				UnifyContext context = new UnifyContext(logFile, log, false, new UnifyResultModel(cons, finiteClosure), usedTasks, placeholderRegistry);
-				Set<Set<UnifyPair>> result = TypeUnify.unifyOderConstraints(unifyCons.getUndConstraints(), oderConstraints, finiteClosure, context);
-				System.out.println("RESULT: " + result);
-				logFile.write("RES: " + result.toString() + "\n");
-				// logFile.flush();
-				results.addAll(result);
+			return x;
 
-				results = results.stream().map(x -> {
-					Optional<Set<UnifyPair>> res = new RuleSet(placeholderRegistry).subst(x.stream().map(y -> {
-						if (y.getPairOp() == PairOperator.SMALLERDOTWC)
-							y.setPairOp(PairOperator.EQUALSDOT);
-						return y; // alle Paare a <.? b erden durch a =. b ersetzt
-					}).collect(Collectors.toCollection(HashSet::new)));
-					if (res.isPresent()) {// wenn subst ein Erg liefert wurde was veraendert
-						return new TypeUnifyTask(context).applyTypeUnificationRules(res.get(), finiteClosure);
-					} else
-						return x; // wenn nichts veraendert wurde wird x zurueckgegeben
-				}).collect(Collectors.toCollection(HashSet::new));
-				System.out.println("RESULT Final: " + results);
-				System.out.println("Constraints for Generated Generics: " + " ???");
-				logFile.write("RES_FINAL: " + results.toString() + "\n");
-				// logFile.flush();
-				logFile.write("PLACEHOLDERS: " + placeholderRegistry);
-				// logFile.flush();
-			}
-		} catch (IOException e) {
-			System.err.println("kein LogFile");
+		};
+
+		logger.debug("Unify:" + unifyCons.toString());
+		logger.info("Unify:" + unifyCons.toString());
+		unifyCons = unifyCons.map(distributeInnerVars);
+		logger.debug("\nUnify_distributeInnerVars: " + unifyCons.toString());
+		// Set<Set<UnifyPair>> results = new HashSet<>(); Nach vorne gezogen
+		logger.debug("FC:\\" + finiteClosure.toString() + "\n");
+		logger.debug(ASTTypePrinter.print(sf));
+		logger.info(ASTTypePrinter.print(sf));
+		// logFile.flush();
+		logger.info("Unify nach Oder-Constraints-Anpassung:" + unifyCons.toString());
+		Set<PlaceholderType> varianceTPHold;
+		Set<PlaceholderType> varianceTPH = new HashSet<>();
+		varianceTPH = varianceInheritanceConstraintSet(unifyCons);
+
+		/*
+		 * PL 2018-11-07 wird in varianceInheritanceConstraintSet erledigt do { //PL 2018-11-05 Huellenbildung Variance auf alle TPHs der Terme auf der jeweiligen //anderen Seite übertragen varianceTPHold = new HashSet<>(varianceTPH); varianceTPH = varianceInheritanceConstraintSet(unifyCons); unifyCons.map( y -> { if ((y.getLhsType() instanceof PlaceholderType) && (y.getRhsType() instanceof PlaceholderType)) { if (((PlaceholderType)y.getLhsType()).getVariance() != 0 &&
+		 * ((PlaceholderType)y.getRhsType()).getVariance() == 0) { ((PlaceholderType)y.getRhsType()).setVariance(((PlaceholderType)y.getLhsType( )).getVariance()); } if (((PlaceholderType)y.getLhsType()).getVariance() == 0 && ((PlaceholderType)y.getRhsType()).getVariance() != 0) { ((PlaceholderType)y.getLhsType()).setVariance(((PlaceholderType)y.getRhsType( )).getVariance()); } } return y; } ); } while (!varianceTPHold.equals(varianceTPH));
+		 */
+
+		// Set<Set<UnifyPair>> result = unify.unifySequential(xConsSet, finiteClosure,
+		// logFile, log);
+		// Set<Set<UnifyPair>> result = unify.unify(xConsSet, finiteClosure);
+		List<Set<Constraint<UnifyPair>>> oderConstraints = unifyCons.getOderConstraints()// .stream().map(x -> {
+		/*
+		 * Set<Set<UnifyPair>> ret = new HashSet<>(); for (Constraint<UnifyPair> y : x) { ret.add(new HashSet<>(y)); } return ret; }).collect(Collectors.toCollection(ArrayList::new))
+		 */;
+
+		if (ConsoleInterface.unifyServerUrl.isPresent()) {
+			UnifyResultModel urm = new UnifyResultModel(cons, finiteClosure);
+			UnifyContext context = new UnifyContext(logger, true, urm, usedTasks, placeholderRegistry);
+			SocketFuture<UnifyResultPacket> future = SocketClient.execute(
+				UnifyRequestPacket.create(finiteClosure, cons, unifyCons, context.placeholderRegistry())
+			);
+			SocketClient.execute(SetAutoclosePacket.create());
+			return future.get().getResultSet(context);
 		}
+		else if (resultmodel) {
+			/* UnifyResultModel Anfang */
+			UnifyResultModel urm = new UnifyResultModel(cons, finiteClosure);
+			UnifyResultListenerImpl li = new UnifyResultListenerImpl();
+			urm.addUnifyResultListener(li);
+			UnifyContext context = new UnifyContext(logger, true, urm, usedTasks, placeholderRegistry);
+			TypeUnify.unifyParallel(unifyCons.getUndConstraints(), oderConstraints, finiteClosure, context);
+			logger.info("RESULT Final: " + li.getResults());
+			logger.info("Constraints for Generated Generics: " + " ???");
+			logFile.write("RES_FINAL: " + li.getResults().toString() + "\n");
+			// logFile.flush();
+			return li.getResults();
+		}
+		/* UnifyResultModel End */
+		else {
+			// Set<Set<UnifyPair>> result = unify.unify(unifyCons.getUndConstraints(),
+			// oderConstraints, finiteClosure, logFile, log, new UnifyResultModel(cons,
+			// finiteClosure));
+			UnifyContext context = new UnifyContext(logger, false, new UnifyResultModel(cons, finiteClosure), usedTasks, placeholderRegistry);
+			Set<Set<UnifyPair>> result = TypeUnify.unifyOderConstraints(unifyCons.getUndConstraints(), oderConstraints, finiteClosure, context);
+			logger.info("RESULT: " + result);
+			logFile.write("RES: " + result.toString() + "\n");
+			// logFile.flush();
+			results.addAll(result);
+
+			results = results.stream().map(x -> {
+				Optional<Set<UnifyPair>> res = new RuleSet(placeholderRegistry).subst(x.stream().map(y -> {
+					if (y.getPairOp() == PairOperator.SMALLERDOTWC)
+						y.setPairOp(PairOperator.EQUALSDOT);
+					return y; // alle Paare a <.? b erden durch a =. b ersetzt
+				}).collect(Collectors.toCollection(HashSet::new)));
+				if (res.isPresent()) {// wenn subst ein Erg liefert wurde was veraendert
+					return new TypeUnifyTask(context).applyTypeUnificationRules(res.get(), finiteClosure);
+				} else
+					return x; // wenn nichts veraendert wurde wird x zurueckgegeben
+			}).collect(Collectors.toCollection(HashSet::new));
+			logger.info("RESULT Final: " + results);
+			logger.info("Constraints for Generated Generics: " + " ???");
+			logger.debug("RES_FINAL: " + results.toString() + "\n");
+			// logFile.flush();
+			logger.debug("PLACEHOLDERS: " + placeholderRegistry);
+			// logFile.flush();
+		}
+
 		return results.stream().map((unifyPairs -> new ResultSet(UnifyTypeFactory.convert(unifyPairs, Pair.generateTPHMap(cons), placeholderRegistry)))).collect(Collectors.toList());
 	}
 
@@ -660,15 +661,15 @@ public class JavaTXCompiler {
 		FileOutputStream output;
 		for (JavaClassName name : classFiles.keySet()) {
 			byte[] bytecode = classFiles.get(name);
-			System.out.println("generating " + name + ".class file ...");
+			defaultLogger.info("generating " + name + ".class file ...");
 			var subPath = preserveHierarchy ? path : Path.of(path.toString(), name.getPackageName().split("\\.")).toFile();
 			File outputFile = new File(subPath, name.getClassName() + ".class");
 			outputFile.getAbsoluteFile().getParentFile().mkdirs();
-			System.out.println(outputFile);
+			defaultLogger.info(outputFile.toString());
 			output = new FileOutputStream(outputFile);
 			output.write(bytecode);
 			output.close();
-			System.out.println(name + ".class file generated");
+			defaultLogger.success(name + ".class file generated");
 		}
 	}
 

src/main/java/de/dhbwstuttgart/core/JavaTXServer.java

@@ -4,13 +4,27 @@ import de.dhbwstuttgart.server.SocketServer;
 
 public class JavaTXServer {
 
-  public void listen(int port) {
+  public static boolean isRunning = false;
+
+  final SocketServer socketServer;
+
+  public JavaTXServer(int port) {
+    this.socketServer = new SocketServer(port);
+  }
+
+  public void listen() {
+    isRunning = true;
+    socketServer.start();
+  }
+
+  public void forceStop() {
     try {
-      SocketServer socketServer = new SocketServer(port);
-      socketServer.start();
-    } catch (Exception e) {
-      e.printStackTrace();
+      socketServer.stop();
     }
+    catch (InterruptedException exception) {
+      System.err.println("Interrupted socketServer: " + exception);
+    }
+    isRunning = false;
   }
 
 

src/main/java/de/dhbwstuttgart/parser/JavaTXParser.java

@@ -7,6 +7,7 @@ import de.dhbwstuttgart.parser.antlr.Java17Parser;
 import de.dhbwstuttgart.parser.scope.JavaClassRegistry;
 import de.dhbwstuttgart.syntaxtree.SourceFile;
 
+import de.dhbwstuttgart.util.Logger;
 import org.antlr.v4.runtime.CharStream;
 import org.antlr.v4.runtime.CharStreams;
 import org.antlr.v4.runtime.CommonTokenStream;
@@ -17,6 +18,9 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class JavaTXParser {
+
+    public static Logger logger = new Logger("Parser");
+
     public static Java17Parser.SourceFileContext parse(File source) throws IOException, java.lang.ClassNotFoundException {
         InputStream stream = new FileInputStream(source);
         // DEPRECATED: ANTLRInputStream input = new ANTLRInputStream(stream);

src/main/java/de/dhbwstuttgart/parser/SyntaxTreeGenerator/FCGenerator.java

@@ -111,7 +111,7 @@ public class FCGenerator {
         //Generics mit gleichem Namen müssen den selben TPH bekommen
         for(GenericTypeVar gtv : forType.getGenerics()){
             if(!gtvs.containsKey(gtv.getName())){
-                TypePlaceholder replacePlaceholder = TypePlaceholder.fresh(new NullToken(), placeholderRegistry);
+                TypePlaceholder replacePlaceholder = TypePlaceholder.fresh(new NullToken());
                 gtvs.put(gtv.getName(), replacePlaceholder);
                 newGTVs.put(gtv.getName(), replacePlaceholder);
             }

src/main/java/de/dhbwstuttgart/parser/SyntaxTreeGenerator/StatementGenerator.java

@@ -1,5 +1,6 @@
 package de.dhbwstuttgart.parser.SyntaxTreeGenerator;
 
+import de.dhbwstuttgart.parser.JavaTXParser;
 import java.lang.reflect.Modifier;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -259,7 +260,7 @@ public class StatementGenerator {
             ret.setStatement();
             return ret;
         default:
-            System.out.println(stmt.getClass());
+            JavaTXParser.logger.info(stmt.getClass());
             throw new NotImplementedException();
         }
     }

src/main/java/de/dhbwstuttgart/parser/SyntaxTreeGenerator/TypeGenerator.java

@@ -74,7 +74,7 @@ public class TypeGenerator {
                 throw new NotImplementedException();
             }
         } else if (!typeContext.LBRACK().isEmpty()) { // ArrayType über eckige Klammer prüfen
-            // System.out.println(unannTypeContext.getText());
+            // JavaTXParser.logger.info(unannTypeContext.getText());
             throw new NotImplementedException();
         }
         /*

src/main/java/de/dhbwstuttgart/server/ServerTaskLogger.java

@@ -0,0 +1,41 @@
+package de.dhbwstuttgart.server;
+
+import de.dhbwstuttgart.util.Logger;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import org.java_websocket.WebSocket;
+
+public class ServerTaskLogger extends Logger {
+
+  private final WebSocket webSocket;
+  private final SocketServer socketServer;
+  private final LogLevel customLogLevel;
+
+  public ServerTaskLogger(WebSocket webSocket, SocketServer socketServer, LogLevel customLogLevel) {
+    this.webSocket = webSocket;
+    this.socketServer = socketServer;
+    this.customLogLevel = customLogLevel;
+  }
+
+  @Override
+  public boolean isLogLevelActive(LogLevel logLevel) {
+    return logLevel.isHigherOrEqualTo(customLogLevel);
+  }
+
+  @Override
+  protected void print(String s, LogLevel logLevel) {
+    String coloredPrefix = this.getPrefix(logLevel);
+    if (logLevel.isHigherOrEqualTo(LogLevel.ERROR)) {
+      socketServer.sendError(webSocket, coloredPrefix + s, false);
+    }
+    else {
+      socketServer.sendMessage(webSocket, coloredPrefix + s);
+    }
+  }
+
+  @Override
+  protected void write(String s) {
+    // under no circumstances write anything to a file
+  }
+
+}

src/main/java/de/dhbwstuttgart/server/SocketClient.java

@@ -1,6 +1,8 @@
 package de.dhbwstuttgart.server;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
+import de.dhbwstuttgart.core.ConsoleInterface;
+import de.dhbwstuttgart.server.packet.IClientToServerPacket;
 import de.dhbwstuttgart.server.packet.IPacket;
 import de.dhbwstuttgart.server.packet.IServerToClientPacket;
 import de.dhbwstuttgart.server.packet.PacketContainer;
@@ -12,10 +14,12 @@ import de.dhbwstuttgart.typeinference.result.ResultSet;
 import de.dhbwstuttgart.typeinference.unify.UnifyContext;
 import de.dhbwstuttgart.typeinference.unify.model.FiniteClosure;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
+import de.dhbwstuttgart.util.Logger;
 import java.net.URI;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CountDownLatch;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -29,39 +33,33 @@ import org.java_websocket.handshake.ServerHandshake;
  */
 public class SocketClient extends WebSocketClient {
 
-  // use a latch to wait until the connection is closed by the remote host
-  private final CountDownLatch closeLatch = new CountDownLatch(1);
-  // temporarily: The received unify result
-  // TODO: replace with uuid and future system, such that responses can be mapped by a uuid to fulfill a Future
-  private UnifyResultPacket unifyResultPacket;
+  public static Logger logger = new Logger("SocketClient");
 
-  public SocketClient(String url) {
-    super(URI.create(url), Map.of(
-      "packetProtocolVersion", SocketServer.packetProtocolVersion
-    ));
-    // make sure, the url is in a valid format
+  /**
+   * The singleton object
+   */
+  private static SocketClient socketClient = null;
+
+  /**
+   * List of futures that are still waiting to be fulfilled
+   */
+  private final Map<String, SocketFuture<?>> responseFutures = new HashMap<>();
+
+  private SocketClient(String url) {
+    super(
+      URI.create(url), // target url
+      //SocketServer.perMessageDeflateDraft, // enable compression
+      Map.of( // headers
+        "packetProtocolVersion", SocketServer.packetProtocolVersion
+      )
+    );
+
+    // make sure the url is in a valid format
     final String regex = "^wss?://(\\w+(\\.\\w+)?)*:(\\d+)$";
     final Matcher matcher = Pattern.compile(regex).matcher(url);
     if (!matcher.find()) {
       throw new RuntimeException("Provided string \"" + url + "\" is not a valid server URL! Use pattern ws(s?)://<host.name>:<port>");
     }
-  }
-
-  public SocketClient(String host, int port, boolean secure) {
-    super(URI.create(String.format("%s://%s:%d/", secure ? "wss" : "ws", host, port)));
-  }
-
-  /**
-   * The main method for connecting, requesting and waiting for the server to unify.
-   * This is synchronized to prevent multiple webSockets connections at the moment, but it is not called from any
-   * thread except the main thread right now and is not necessary at all, probably. Maybe remove it later
-   */
-  synchronized public List<ResultSet> execute(
-    FiniteClosure finiteClosure,
-    ConstraintSet<Pair> constraintSet,
-    ConstraintSet<UnifyPair> unifyConstraintSet,
-    UnifyContext context
-  ) throws JsonProcessingException {
 
     try {
       // wait for the connection to be set up
@@ -70,89 +68,135 @@ public class SocketClient extends WebSocketClient {
       if (this.getReadyState() != ReadyState.OPEN) {
         throw new RuntimeException("WebSocket Client could not connect to remote host at " + this.uri);
       }
-
-      // send the unify task request
-      UnifyRequestPacket packet = new UnifyRequestPacket(finiteClosure, constraintSet, unifyConstraintSet, context.placeholderRegistry());
-      String json = PacketContainer.serialize(packet);
-      this.send(json);
-
-      // block the thread, until the connection is closed by the remote host (usually after sending the results)
-      this.waitUntilClosed();
-      // wait for the connection to fully close
-      this.closeBlocking();
     } catch (InterruptedException exception) {
-      System.err.println("Server connection interrupted: " + exception);
-      this.notifyAll();
-      throw new RuntimeException("Aborted server connection", exception);
-    }
-    catch (Exception exception) {
-      throw new RuntimeException("Exception occurred in server connection: ", exception);
+      throw new RuntimeException(exception);
     }
 
-    // detect error cases, in which no error was thrown, but also no result was sent back from the server
-    if (this.unifyResultPacket == null) {
-      throw new RuntimeException("Did not receive server response but closed connection already");
-    }
+    // add a shutdown hook to close the connection when the process ends or is stopped by a SIGINT signal
+    Runtime.getRuntime().addShutdownHook(new Thread(this::close));
+  }
 
-    return unifyResultPacket.getResultSet(context);
+  private SocketClient(String host, int port, boolean secure) throws InterruptedException {
+    this(String.format("%s://%s:%d/", secure ? "wss" : "ws", host, port));
   }
 
   /**
-   *  Specific client-side implementations to handle incoming packets
+   * Singleton access method, creates one if none is available
+   *
+   * @return The one and only socketClient
+   */
+  private static SocketClient initializeClient() {
+    if (socketClient == null) {
+      socketClient = new SocketClient(ConsoleInterface.unifyServerUrl.get());
+    }
+    return socketClient;
+  }
+
+  /**
+   * Send a packet to the server (connection will be created, if none is found) and return a future
+   * for the response packet
+   */
+  synchronized public static <T extends IServerToClientPacket> SocketFuture<T> execute(IClientToServerPacket<T> packet) {
+    SocketClient client = initializeClient();
+
+    /*
+     * Create a future that will be associated with the packet and eventually completed
+     */
+    SocketFuture<T> future = packet.getFuture();
+    if (!future.isDone()) {
+      client.responseFutures.put(future.futureId, future);
+    }
+
+    /*
+     * Establish connection, if not already done.
+     * Serialize the packet and send it to the server.
+     * Return the future to be handled by the caller.
+     */
+    try {
+      String json = PacketContainer.serialize(packet);
+      client.send(json);
+    } catch (Exception exception) {
+      logger.exception(exception);
+      throw new RuntimeException("Exception occurred in server connection: ", exception);
+    }
+
+    return future;
+  }
+
+  /**
+   * Shortcut for waiting and retrieving the response immediately
+   *
+   * @param packet The packet to send
+   * @param <T>    The type of response packet to await
+   * @return The response packet, once it is received
+   */
+  public static <T extends IServerToClientPacket> T executeAndGet(IClientToServerPacket<T> packet) {
+    return SocketClient.execute(packet).get();
+  }
+
+  /**
+   * Specific client-side implementations to handle incoming packets
    */
   protected void handleReceivedPacket(IPacket packet) {
-    if (packet instanceof IServerToClientPacket serverToClientPacket) {
-
-      try {
-        serverToClientPacket.onHandle(this.getConnection(), this);
-      }
-      catch (Exception exception) {
-        this.closeLatch.countDown();
-        this.close();
-        throw exception;
-      }
-
+    if (!(packet instanceof IServerToClientPacket serverToClientPacket)) {
+      System.err.println("Received package of invalid type + " + packet.getClass().getName());
+      this.close();
       return;
     }
 
-    System.err.println("Received package of invalid type + " + packet.getClass().getName());
-    this.close();
+    serverToClientPacket.onHandle(this.getConnection(), this);
   }
 
-  public void setUnifyResultSets(UnifyResultPacket unifyResultPacket) {
-    this.unifyResultPacket = unifyResultPacket;
+  /**
+   * Complete a registered future, so it can be handled by whoever executed the creator task
+   *
+   * @param id      The associated id for this future
+   * @param trigger The object triggering the completion
+   */
+  public void completeResponseFuture(String id, IServerToClientPacket trigger) {
+    SocketFuture<?> future = this.responseFutures.remove(id);
+    if (future == null) return;
+    if (!future.accept(trigger)) {
+      throw new RuntimeException("Packet " + trigger.getClass().getName() + " tried to complete future, but was not allowed to");
+    }
+  }
+
+  public static void closeIfOpen() {
+    if (socketClient != null && socketClient.isOpen()) {
+      socketClient.close();
+    }
   }
 
   @Override
   public void onOpen(ServerHandshake handshakedata) {
-    System.out.println("Connected to server with status " + handshakedata.getHttpStatus());
+    logger.success("Connected to server with status " + handshakedata.getHttpStatus());
   }
 
   @Override
   public void onMessage(String message) {
-    // System.out.println("received: " + message);
+    // logger.info("received: " + message);
     IPacket packet = PacketContainer.deserialize(message);
     this.handleReceivedPacket(packet);
   }
 
   @Override
   public void onClose(int code, String reason, boolean remote) {
-    System.out.println(
+    logger.info(
       "Disconnected from server " +
         "with code " + code + " " +
         (reason.isEmpty() ? "" : "and reason " + reason + " ") +
         "(closed by remote: " + remote + ")"
     );
-    this.closeLatch.countDown();
+
+    if (!this.responseFutures.isEmpty()) {
+      throw new RuntimeException("Server closed before all required tasks were answered");
+    }
   }
 
   @Override
   public void onError(Exception e) {
-    System.out.println("Error: " + e.getMessage());
-    e.printStackTrace();
+    logger.exception(e);
+    throw new RuntimeException(e);
   }
 
-  public void waitUntilClosed() throws InterruptedException {
-    closeLatch.await();
-  }
 }

src/main/java/de/dhbwstuttgart/server/SocketFuture.java

@@ -0,0 +1,48 @@
+package de.dhbwstuttgart.server;
+
+import de.dhbwstuttgart.server.packet.IServerToClientPacket;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+
+public class SocketFuture<T extends IServerToClientPacket> extends CompletableFuture<T> {
+
+  public final String futureId = UUID.randomUUID().toString();
+
+  public final List<Class<T>> allowedTriggers;
+
+  public SocketFuture(List<Class<T>> allowedTriggers) {
+    this.allowedTriggers = allowedTriggers;
+  }
+
+  public boolean accept(IServerToClientPacket trigger) {
+    if (this.allowedTriggers.contains(trigger.getClass())) {
+      this.complete((T)trigger);
+      return true;
+    }
+    return false;
+  }
+
+  @Override
+  public T get() {
+    try {
+      return super.get();
+    }
+    catch (InterruptedException | ExecutionException exception) {
+      throw new RuntimeException(exception);
+    }
+  }
+
+  /**
+   * Special case where the future is immediately fulfilled without a response package similar to
+   * <code>CompletableFuture.completedFuture()</code> but without a value
+   */
+  public static <R extends IServerToClientPacket> SocketFuture<R> completedFuture() {
+    SocketFuture<R> dummyFuture = new SocketFuture<>(new ArrayList<>(0));
+    dummyFuture.complete(null);
+    return dummyFuture;
+  }
+
+}

src/main/java/de/dhbwstuttgart/server/SocketServer.java

@@ -6,76 +6,104 @@ import de.dhbwstuttgart.server.packet.IClientToServerPacket;
 import de.dhbwstuttgart.server.packet.IPacket;
 import de.dhbwstuttgart.server.packet.MessagePacket;
 import de.dhbwstuttgart.server.packet.PacketContainer;
+import de.dhbwstuttgart.util.Logger;
 import java.net.InetSocketAddress;
-import java.util.Objects;
+import java.util.Collections;
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.SynchronousQueue;
+import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.java_websocket.WebSocket;
+import org.java_websocket.drafts.Draft;
+import org.java_websocket.drafts.Draft_6455;
+import org.java_websocket.extensions.permessage_deflate.PerMessageDeflateExtension;
 import org.java_websocket.handshake.ClientHandshake;
 import org.java_websocket.server.WebSocketServer;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 public class SocketServer extends WebSocketServer {
 
+  public static Logger logger = new Logger("SocketServer");
+  public static final int maxTasksPerSession = 100;
+  private static boolean serverRunning = false;
+
   /**
    * Increase this every time a breaking change to the server communication is done.
-   * This will prevent errors when server version and client version do not match.
+   * This will prevent errors when the server version and client version do not match.
    */
   public static final String packetProtocolVersion = "1";
 
-  public static final Logger log = LoggerFactory.getLogger(SocketServer.class);
+  // create an executor for tasks that will always keep at least one task around
+  private final ThreadPoolExecutor taskExecutor = new ThreadPoolExecutor(1, Integer.MAX_VALUE,60L, TimeUnit.SECONDS, new SynchronousQueue<>());
+  // create an executor for scheduling timeouts
+  private final ScheduledExecutorService timeoutExecutor = Executors.newSingleThreadScheduledExecutor();
 
   public SocketServer(int port) {
     super(new InetSocketAddress(port));
+    this.setConnectionLostTimeout(30);
+
+    serverRunning = true;
+    // add a shutdown hook to close all connections when the process ends or is stopped by a SIGINT signal
+    Runtime.getRuntime().addShutdownHook(new Thread(this::onShutdown));
+  }
+
+  public static boolean isServerRunning() {
+    return serverRunning;
+  }
+
+  private void onShutdown() {
+    serverRunning = false;
+    try {
+      for (var webSocket : this.getConnections()) {
+        this.sendError(webSocket, "Sorry, i am shutting down. You are now on your own, good Luck!", true);
+        webSocket.close();
+      }
+      this.stop();
+      taskExecutor.shutdown();
+      timeoutExecutor.shutdown();
+    } catch (InterruptedException exception) {
+      // we are shutting down anyway
+    }
   }
 
   @Override
   public void onOpen(WebSocket webSocket, ClientHandshake clientHandshake) {
     String ppv = clientHandshake.getFieldValue("packetProtocolVersion");
     if (!ppv.equals(packetProtocolVersion)) {
-      try {
-        ErrorPacket errorPacket = ErrorPacket.create(
-          "Mismatch in packet protocol version! Client (you): " + ppv + " and Server (me): " + packetProtocolVersion,
-          true
-        );
-        webSocket.send(PacketContainer.serialize(errorPacket));
-      }
-      catch (JsonProcessingException exception) {
-        System.err.println("Failed to serialize json: " + exception);
-      }
+      this.sendError(webSocket,
+        "Mismatch in packet protocol version! Client (you): \"" + ppv + "\" and Server (me): \"" + packetProtocolVersion + "\"",
+        true
+      );
       webSocket.close(1);
       return;
     }
 
-
-    SocketData socketData = new SocketData(UUID.randomUUID().toString());
-    webSocket.setAttachment(socketData);
-    System.out.println("New connection: " + socketData.id + " (with ppv " + ppv + ")");
+    SocketData socketData = new SocketData(webSocket);
+    logger.info("New connection: " + socketData.id + " (with ppv " + ppv + ")");
 
     try {
       sendMessage(webSocket, "Welcome to the server!");
 
       // wait 10 seconds for the client to send a task and close the connection if nothing has been received until then
-      try (ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor()) {
-        Runnable task = () -> {
-          if (webSocket.<SocketData>getAttachment().unhandledTasks.get() == 0 || !webSocket.isOpen()) {
+      final int secondsUntilTimeout = 10;
+      timeoutExecutor.schedule(() -> {
+          if (webSocket.<SocketData>getAttachment().totalTasks.get() > 0 || !webSocket.isOpen()) {
             return;
           }
-          sendMessage(webSocket, "No task received after 10 seconds. Closing connection...");
+          sendMessage(webSocket, "No task received after " + secondsUntilTimeout + " seconds. Closing connection...");
           webSocket.close();
-        };
-        executor.schedule(task, 10, TimeUnit.SECONDS);
-        executor.shutdown();
-      }
+        },
+        secondsUntilTimeout,
+        TimeUnit.SECONDS
+      );
 
       // and finally, when your program wants to exit
     } catch (Exception e) {
-      log.error("e: ", e);
+      logger.exception(e);
       webSocket.close(1, e.getMessage());
     }
   }
@@ -83,8 +111,8 @@ public class SocketServer extends WebSocketServer {
   @Override
   public void onClose(WebSocket webSocket, int code, String reason, boolean remote) {
     SocketData socketData = webSocket.getAttachment();
-    System.out.println("Connection closed: " + socketData.id);
-    System.out.println(
+    logger.info("Connection closed: " + socketData.id);
+    logger.info(
       "Disconnected client " + socketData.id + " " +
         "with code " + code + " " +
         (reason.isEmpty() ? "" : "and reason " + reason + " ") +
@@ -95,24 +123,28 @@ public class SocketServer extends WebSocketServer {
 
   @Override
   public void onMessage(WebSocket webSocket, String s) {
-    // System.out.println("Received: " + s.substring(0, 50));
+    // logger.info("Received: " + s.substring(0, 50));
     IPacket reconstructedPacket = PacketContainer.deserialize(s);
     try {
       this.onPacketReceived(webSocket, reconstructedPacket);
     } catch (JsonProcessingException e) {
-      this.log("Error on processing incoming package: " + e.getMessage(), webSocket);
+      logger.exception(e);
+      this.log(webSocket, "Error on processing incoming package: " + e.getMessage());
     }
   }
 
   @Override
   public void onError(WebSocket webSocket, Exception e) {
-    log(e.getMessage(), webSocket);
-    webSocket.close();
+    if (webSocket != null) {
+      log(webSocket, e.getMessage());
+      webSocket.close();
+    }
+    logger.exception(e);
   }
 
   @Override
   public void onStart() {
-    System.out.println("Websocket server started on port " + this.getPort());
+    logger.success("Websocket server started on port " + this.getPort());
   }
 
   /**
@@ -120,45 +152,42 @@ public class SocketServer extends WebSocketServer {
    */
   public void sendMessage(WebSocket webSocket, String text) {
     try {
-      MessagePacket message = new MessagePacket();
-      message.message = text;
+      MessagePacket message = MessagePacket.create(text);
       webSocket.send(PacketContainer.serialize(message));
     } catch (Exception e) {
       System.err.println("Failed to send message: " + text);
-      log.error("e: ", e);
+      logger.exception(e);
     }
   }
 
   /**
    * A shorthand method for sending error messages to the client
    */
-  public void sendError(WebSocket webSocket, String text) {
+  public void sendError(WebSocket webSocket, String text, boolean isFatal) {
     try {
-      ErrorPacket error = new ErrorPacket();
-      error.error = text;
+      ErrorPacket error = ErrorPacket.create(text, isFatal);
       webSocket.send(PacketContainer.serialize(error));
     } catch (Exception e) {
-      System.err.println("Failed to send error: " + text);
-      log.error("e: ", e);
+      logger.exception(e);
+      log(webSocket, "Failed to send error: " + text);
     }
   }
 
   /**
-   *  The server-side implementation on how to handle certain packets when received
+   * The server-side implementation on how to handle certain packets when received
    */
   private void onPacketReceived(WebSocket webSocket, IPacket packet) throws JsonProcessingException {
     SocketData socketData = webSocket.getAttachment();
 
-    // limit the amount of tasks per connection
-    final int maxTasks = 100;
-    if (socketData.totalTasks.get() >= maxTasks) {
-      sendError(webSocket, "Exceeded the maximum amount of " + maxTasks + " tasks per session");
+    // limit the number of tasks per connection
+    if (socketData.totalTasks.get() >= maxTasksPerSession) {
+      sendError(webSocket, "Exceeded the maximum amount of " + maxTasksPerSession + " tasks per session", true);
       webSocket.close();
       return;
     }
 
-    // only allow packets, that are meant to be handled by the server
-    if (!(packet instanceof IClientToServerPacket clientToServerPacket)) {
+    // only allow packets that are meant to be handled by the server
+    if (!(packet instanceof IClientToServerPacket<?> clientToServerPacket)) {
       sendMessage(webSocket, "The package of type " + packet.getClass().getName() + " is not handled by the server!");
       return;
     }
@@ -167,22 +196,24 @@ public class SocketServer extends WebSocketServer {
     socketData.unhandledTasks.incrementAndGet();
     socketData.totalTasks.incrementAndGet();
 
-    // add the packet to the queue, so it can be started by the worker
+    // add the packet to the queue so it can be started by the worker
     CompletableFuture.runAsync(() -> {
       clientToServerPacket.onHandle(webSocket, this);
-
-      // if the websocket has 0 unhandled Tasks, close the connection
       int remainingUnhandledTasks = socketData.unhandledTasks.decrementAndGet();
-      if (remainingUnhandledTasks <= 0) {
-        sendMessage(webSocket, "All requested tasks finished! Closing connection...");
-        webSocket.close();
+
+      if (socketData.closeIfNoTasksLeft) {
+        // if the websocket has 0 unhandled Tasks, close the connection
+        if (remainingUnhandledTasks <= 0) {
+          sendMessage(webSocket, "All requested tasks finished! Closing connection...");
+          webSocket.close();
+        }
       }
-    });
+    }, taskExecutor);
   }
 
-  public void log(String msg, WebSocket webSocket) {
-    SocketData socketData = webSocket == null ? new SocketData("???") : webSocket.getAttachment();
-    System.out.println("["+socketData.id+"] " + msg);
+  public void log(WebSocket webSocket, String msg) {
+    String socketId = (webSocket == null) ? "???" : webSocket.<SocketData>getAttachment().id;
+    logger.info("[" + socketId + "] " + msg);
   }
 
   /**
@@ -194,10 +225,11 @@ public class SocketServer extends WebSocketServer {
     public final String id;
     public final AtomicInteger unhandledTasks = new AtomicInteger(0);
     public final AtomicInteger totalTasks = new AtomicInteger(0);
+    public boolean closeIfNoTasksLeft = false;
 
-    public SocketData(String id) {
-      this.id = id;
+    public SocketData(WebSocket webSocket) {
+      this.id = UUID.randomUUID().toString();
+      webSocket.setAttachment(this);
     }
   }
-
 }

src/main/java/de/dhbwstuttgart/server/packet/DebugPacket.java

@@ -2,6 +2,7 @@ package de.dhbwstuttgart.server.packet;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import de.dhbwstuttgart.server.SocketClient;
+import de.dhbwstuttgart.server.SocketFuture;
 import de.dhbwstuttgart.server.SocketServer;
 import de.dhbwstuttgart.server.packet.dataContainers.serialized.ISerialNode;
 import de.dhbwstuttgart.server.packet.dataContainers.serialized.SerialList;
@@ -10,7 +11,7 @@ import de.dhbwstuttgart.server.packet.dataContainers.serialized.SerialUUID;
 import de.dhbwstuttgart.server.packet.dataContainers.serialized.SerialValue;
 import org.java_websocket.WebSocket;
 
-public class DebugPacket implements IClientToServerPacket, IServerToClientPacket {
+public class DebugPacket implements IClientToServerPacket.Void, IServerToClientPacket {
 
   public SerialUUID a1;
   public SerialUUID a2;
@@ -22,9 +23,13 @@ public class DebugPacket implements IClientToServerPacket, IServerToClientPacket
   public SerialValue<?> d2;
 
   @JsonIgnore
-  public void onHandle(WebSocket webSocket, SocketClient socketServer) {}
+  public void onHandle(WebSocket webSocket, SocketClient socketClient) {}
 
   @JsonIgnore
   public void onHandle(WebSocket webSocket, SocketServer socketServer) {}
 
+  @JsonIgnore
+  public SocketFuture<IServerToClientPacket> getFuture() {
+    return SocketFuture.completedFuture();
+  }
 }

src/main/java/de/dhbwstuttgart/server/packet/ErrorPacket.java

@@ -2,16 +2,17 @@ package de.dhbwstuttgart.server.packet;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import de.dhbwstuttgart.server.SocketClient;
+import de.dhbwstuttgart.server.SocketFuture;
 import de.dhbwstuttgart.server.SocketServer;
 import org.java_websocket.WebSocket;
 
 /**
  * A packet to send simple error messages between the client and the server
  */
-public class ErrorPacket implements IClientToServerPacket, IServerToClientPacket {
+public class ErrorPacket implements IServerToClientPacket {
 
   /**
-   * The error endpoint for messages from the server, that should be logged out outputted
+   * The error endpoint for messages from the server that should be logged out as errors and possibly abort the process
    */
   public String error;
   public boolean isFatal;
@@ -27,15 +28,9 @@ public class ErrorPacket implements IClientToServerPacket, IServerToClientPacket
 
   @JsonIgnore
   public void onHandle(WebSocket webSocket, SocketClient socketClient) {
-    System.err.println("[socket] " + "ErrorPacket: " + this.error);
+    SocketClient.logger.exception(new RuntimeException(this.error));
     if (this.isFatal) {
-      throw new RuntimeException("Received fatal error from server: " + this.error);
+      socketClient.close(1, "Received fatal error from server");
     }
   }
-
-  @JsonIgnore
-  public void onHandle(WebSocket webSocket, SocketServer socketServer) {
-    socketServer.log("ErrorPacket: " + this.error, webSocket);
-  }
-
 }

src/main/java/de/dhbwstuttgart/server/packet/IClientToServerPacket.java

@@ -1,12 +1,26 @@
 package de.dhbwstuttgart.server.packet;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
+import de.dhbwstuttgart.server.SocketFuture;
 import de.dhbwstuttgart.server.SocketServer;
 import org.java_websocket.WebSocket;
 
-public interface IClientToServerPacket extends IPacket {
+/**
+ * A packet that will be sent to the server. Use <code>Void</code> Sub-Interface for packets without response
+ *
+ * @param <T>   The response packet that will fulfill the future.
+ */
+public interface IClientToServerPacket<T extends IServerToClientPacket> extends IPacket {
 
   @JsonIgnore
   void onHandle(WebSocket webSocket, SocketServer socketServer);
 
+  @JsonIgnore
+  SocketFuture<T> getFuture();
+
+  /**
+   * Special case, where the packet will remain unanswered by the server
+   */
+  interface Void extends IClientToServerPacket<IServerToClientPacket> {}
 }
+

src/main/java/de/dhbwstuttgart/server/packet/InvalidPacket.java

@@ -2,13 +2,14 @@ package de.dhbwstuttgart.server.packet;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import de.dhbwstuttgart.server.SocketClient;
+import de.dhbwstuttgart.server.SocketFuture;
 import de.dhbwstuttgart.server.SocketServer;
 import org.java_websocket.WebSocket;
 
 /**
- * A fallback packet that is generated, if the received json could not be mapped to an existing package
+ * A fallback packet that is generated if the received JSON could not be mapped to an existing package
  */
-public class InvalidPacket implements IClientToServerPacket, IServerToClientPacket {
+public class InvalidPacket implements IClientToServerPacket.Void, IServerToClientPacket {
 
   /**
    * If available, the error that caused this package to appear
@@ -18,12 +19,17 @@ public class InvalidPacket implements IClientToServerPacket, IServerToClientPack
 
   @JsonIgnore
   public void onHandle(WebSocket webSocket, SocketClient socketClient) {
-    System.err.println("[socket] " + "InvalidPacket: " + this.error);
+    SocketClient.logger.error("InvalidPacket: " + this.error);
   }
 
   @JsonIgnore
   public void onHandle(WebSocket webSocket, SocketServer socketServer) {
-    socketServer.log("InvalidPacket: " + this.error, webSocket);
+    socketServer.log(webSocket, "InvalidPacket: " + this.error);
+  }
+
+  @JsonIgnore
+  public SocketFuture<IServerToClientPacket> getFuture() {
+    return SocketFuture.completedFuture();
   }
 
 }

src/main/java/de/dhbwstuttgart/server/packet/MessagePacket.java

@@ -2,16 +2,17 @@ package de.dhbwstuttgart.server.packet;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import de.dhbwstuttgart.server.SocketClient;
+import de.dhbwstuttgart.server.SocketFuture;
 import de.dhbwstuttgart.server.SocketServer;
 import org.java_websocket.WebSocket;
 
 /**
  * A packet to send simple informational messages between the client and the server
  */
-public class MessagePacket implements IClientToServerPacket, IServerToClientPacket {
+public class MessagePacket implements IClientToServerPacket.Void, IServerToClientPacket {
 
   /**
-   * The informational message from the server, that should be logged out outputted
+   * The informational message from the server that should be logged out outputted
    */
   public String message;
 
@@ -24,13 +25,16 @@ public class MessagePacket implements IClientToServerPacket, IServerToClientPack
 
   @JsonIgnore
   public void onHandle(WebSocket webSocket, SocketClient socketClient) {
-    System.err.println("[socket] " + this.message);
-
+    SocketClient.logger.info("SocketMessage: " + this.message);
   }
 
   @JsonIgnore
   public void onHandle(WebSocket webSocket, SocketServer socketServer) {
-    socketServer.log(this.message, webSocket);
+    socketServer.log(webSocket, this.message);
   }
 
+  @JsonIgnore
+  public SocketFuture<IServerToClientPacket> getFuture() {
+    return SocketFuture.completedFuture();
+  }
 }

src/main/java/de/dhbwstuttgart/server/packet/PacketContainer.java

@@ -3,6 +3,7 @@ package de.dhbwstuttgart.server.packet;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import de.dhbwstuttgart.util.Logger;
 
 /**
  * A wrapper for the packet to ensure correct serialization/deserialization and make it possible to detect the matching
@@ -24,13 +25,14 @@ public class PacketContainer {
   public UnifyRequestPacket unifyRequestPacket = null;
   public UnifyResultPacket unifyResultPacket = null;
   public DebugPacket debugPacket = null;
+  public SetAutoclosePacket setAutoclosePacket = null;
 
 
   /**
    * Generate the JSON string for the given packet
    *
    * @param packet The packet to serialize
-   * @return The json representation of the packet
+   * @return The JSON representation of the packet
    */
   public static String serialize(IPacket packet) throws JsonProcessingException {
     objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
@@ -46,7 +48,11 @@ public class PacketContainer {
       container.unifyResultPacket = (UnifyResultPacket) packet;
     else if (packet instanceof DebugPacket)
       container.debugPacket = (DebugPacket) packet;
+    else if (packet instanceof SetAutoclosePacket)
+      container.setAutoclosePacket = (SetAutoclosePacket) packet;
     // Add new packets here and in the deserialize method
+    else
+      throw new RuntimeException("Cannot map packet to any known packet class");
 
     return objectMapper.writeValueAsString(container);
   }
@@ -75,11 +81,13 @@ public class PacketContainer {
         return container.unifyResultPacket;
       if (container.debugPacket != null)
         return container.debugPacket;
+      if (container.setAutoclosePacket != null)
+        return container.setAutoclosePacket;
       // Add new packets here and in the serialize method
 
       throw new RuntimeException("Cannot map received json to any known packet class");
     } catch (Exception e) {
-      System.out.println(e);
+      (new Logger()).exception(e);
       InvalidPacket packet = new InvalidPacket();
       packet.error = e.getMessage();
       return packet;

src/main/java/de/dhbwstuttgart/server/packet/SetAutoclosePacket.java

@@ -0,0 +1,32 @@
+package de.dhbwstuttgart.server.packet;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import de.dhbwstuttgart.server.SocketClient;
+import de.dhbwstuttgart.server.SocketFuture;
+import de.dhbwstuttgart.server.SocketServer;
+import org.java_websocket.WebSocket;
+
+/**
+ * Normally, a connection stays open until either the client or the server process ends.
+ * Send this packet to inform the server that the connection can be closed once all tasks are done
+ */
+public class SetAutoclosePacket implements IClientToServerPacket.Void {
+
+  public int dummyProperty = 1;
+
+  @JsonIgnore
+  public static SetAutoclosePacket create() {
+    return new SetAutoclosePacket();
+  }
+
+  @JsonIgnore
+  public void onHandle(WebSocket webSocket, SocketServer socketServer) {
+    webSocket.<SocketServer.SocketData>getAttachment().closeIfNoTasksLeft = true;
+    socketServer.log(webSocket, "Marked connection as autoclose");
+  }
+
+  @JsonIgnore
+  public SocketFuture<IServerToClientPacket> getFuture() {
+    return SocketFuture.completedFuture();
+  }
+}

src/main/java/de/dhbwstuttgart/server/packet/UnifyRequestPacket.java

@@ -1,6 +1,9 @@
 package de.dhbwstuttgart.server.packet;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
+import de.dhbwstuttgart.core.ConsoleInterface;
+import de.dhbwstuttgart.server.ServerTaskLogger;
+import de.dhbwstuttgart.server.SocketFuture;
 import de.dhbwstuttgart.server.SocketServer;
 import de.dhbwstuttgart.server.packet.dataContainers.KeyStorage;
 import de.dhbwstuttgart.server.packet.dataContainers.serialized.SerialList;
@@ -19,18 +22,17 @@ import de.dhbwstuttgart.typeinference.unify.model.FiniteClosure;
 import de.dhbwstuttgart.typeinference.unify.model.PlaceholderType;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyType;
-import java.io.FileWriter;
-import java.io.IOException;
-import java.io.Writer;
+import de.dhbwstuttgart.util.Logger;
 import java.util.ArrayList;
 import java.util.HashSet;
+import java.util.List;
 import java.util.concurrent.ForkJoinPool;
 import org.java_websocket.WebSocket;
 
 /**
  * A packet to send all required data for the unification algorithm to the server and request the unification
  */
-public class UnifyRequestPacket implements IClientToServerPacket {
+public class UnifyRequestPacket implements IClientToServerPacket<UnifyResultPacket> {
 
   public SerialMap finiteClosure;
   public SerialMap constraintSet;
@@ -38,30 +40,33 @@ public class UnifyRequestPacket implements IClientToServerPacket {
   public SerialMap serialKeyStorage;
   public SerialValue<?> placeholders;
   public SerialList<SerialMap> factoryplaceholders;
+  public String futureId;
+  public int logLevel;
 
   @JsonIgnore
   private KeyStorage keyStorage = new KeyStorage();
   @JsonIgnore
   private boolean keyStorageLoaded = false;
 
-  public UnifyRequestPacket() {}
-
-  public UnifyRequestPacket(
+  public static UnifyRequestPacket create(
     FiniteClosure finiteClosure,
     ConstraintSet<Pair> constraintSet,
     ConstraintSet<UnifyPair> unifyConstraintSet,
     PlaceholderRegistry placeholderRegistry
   ) {
-    // store contraint and finite closure
-    this.finiteClosure = finiteClosure.toSerial(keyStorage);
-    this.constraintSet = constraintSet.toSerial(keyStorage);
-    this.unifyConstraintSet = unifyConstraintSet.toSerial(keyStorage);
+    UnifyRequestPacket packet = new UnifyRequestPacket();
+    // store constraint and finite closure
+    packet.finiteClosure = finiteClosure.toSerial(packet.keyStorage);
+    packet.constraintSet = constraintSet.toSerial(packet.keyStorage);
+    packet.unifyConstraintSet = unifyConstraintSet.toSerial(packet.keyStorage);
     // store placeholder registry
-    var serialRegistry = placeholderRegistry.toSerial(keyStorage);
-    this.placeholders = serialRegistry.getValue("ph");
-    this.factoryplaceholders = serialRegistry.getList("factoryPh").assertListOfMaps();
+    var serialRegistry = placeholderRegistry.toSerial(packet.keyStorage);
+    packet.placeholders = serialRegistry.getValue("ph");
+    packet.factoryplaceholders = serialRegistry.getList("factoryPh").assertListOfMaps();
     // store referenced objects separately
-    this.serialKeyStorage = keyStorage.toSerial(keyStorage);
+    packet.serialKeyStorage = packet.keyStorage.toSerial(packet.keyStorage);
+    packet.logLevel = ConsoleInterface.logLevel.getValue();
+    return packet;
   }
 
 
@@ -94,15 +99,22 @@ public class UnifyRequestPacket implements IClientToServerPacket {
   @JsonIgnore
   public void onHandle(WebSocket webSocket, SocketServer socketServer) {
     socketServer.sendMessage(webSocket, "You requested a unify! Please wait until I calculated everything...");
-    System.out.println("Client " + webSocket.<SocketServer.SocketData>getAttachment().id + " requested a unification. Starting now...");
+    socketServer.log(webSocket, "Client requested a unification. Starting now...");
 
     try {
       var placeholderRegistry = new PlaceholderRegistry();
       ArrayList<String> existingPlaceholders = (ArrayList) this.placeholders.getOf(ArrayList.class);
       existingPlaceholders.forEach(placeholderRegistry::addPlaceholder);
 
-      var unifyContext = new UnifyContext(Writer.nullWriter(), false, true,
-        new UnifyResultModel(new ConstraintSet<>(), new FiniteClosure(new HashSet<>(), null, placeholderRegistry)),
+      Logger logger = new ServerTaskLogger(
+        webSocket,
+        socketServer,
+        Logger.LogLevel.fromValue(
+          Math.max(this.logLevel, Logger.LogLevel.INFO.getValue())
+        )
+      );
+      var unifyContext = new UnifyContext(logger, true,
+        new UnifyResultModel(new ConstraintSet<>(), new FiniteClosure(new HashSet<>(), logger, placeholderRegistry)),
         new UnifyTaskModel(), ForkJoinPool.commonPool(), placeholderRegistry
       );
 
@@ -129,17 +141,24 @@ public class UnifyRequestPacket implements IClientToServerPacket {
 
       var resultSets = resultListener.getResults();
 
-      System.out.println("Finished unification for client " + webSocket.<SocketServer.SocketData>getAttachment().id);
+      socketServer.log(webSocket, "Finished unification");
       socketServer.sendMessage(webSocket, "Unification finished. Found " + resultSets.size() + " result sets");
 
       if (webSocket.isOpen()) {
-        UnifyResultPacket resultPacket = UnifyResultPacket.create(resultSets);
+        UnifyResultPacket resultPacket = UnifyResultPacket.create(resultSets, futureId);
         webSocket.send(PacketContainer.serialize(resultPacket));
       }
     } catch (Exception e) {
-      System.err.println(e);
-      SocketServer.log.error("e: ", e);
+      SocketServer.logger.exception(e);
+      socketServer.log(webSocket, e.getMessage());
     }
   }
 
+  @JsonIgnore
+  public SocketFuture<UnifyResultPacket> getFuture() {
+    var future = new SocketFuture<>(List.of(UnifyResultPacket.class));
+    futureId = future.futureId;
+    return future;
+  }
+
 }

src/main/java/de/dhbwstuttgart/server/packet/UnifyResultPacket.java

@@ -18,12 +18,14 @@ public class UnifyResultPacket implements IServerToClientPacket {
 
   public SerialList<ISerialNode> results;
   public SerialMap keyStorage;
+  public String futureId;
 
-  public static UnifyResultPacket create(List<ResultSet> resultSets) {
+  public static UnifyResultPacket create(List<ResultSet> resultSets, String futureId) {
     UnifyResultPacket serialized = new UnifyResultPacket();
     KeyStorage keyStorage = new KeyStorage();
     serialized.results = SerialList.fromMapped(resultSets, resultSet -> resultSet.toSerial(keyStorage));
     serialized.keyStorage = keyStorage.toSerial(keyStorage);
+    serialized.futureId = futureId;
     return serialized;
   }
 
@@ -35,8 +37,8 @@ public class UnifyResultPacket implements IServerToClientPacket {
 
   @JsonIgnore
   public void onHandle(WebSocket webSocket, SocketClient socketClient) {
-    System.out.println("[socket] Received unify result");
-    socketClient.setUnifyResultSets(this);
+    SocketClient.logger.info("Received unify result");
+    socketClient.completeResponseFuture(futureId, this);
   }
 
 

src/main/java/de/dhbwstuttgart/syntaxtree/SyntaxTree.java

@@ -0,0 +1,8 @@
+package de.dhbwstuttgart.syntaxtree;
+
+import de.dhbwstuttgart.util.Logger;
+
+public class SyntaxTree {
+
+  public static Logger logger = new Logger("SyntaxTree");
+}

src/main/java/de/dhbwstuttgart/syntaxtree/factory/NameGenerator.java

@@ -0,0 +1,98 @@
+package de.dhbwstuttgart.syntaxtree.factory;
+
+import de.dhbwstuttgart.core.JavaTXCompiler;
+import de.dhbwstuttgart.core.JavaTXServer;
+
+public class NameGenerator {
+
+    private static String strNextName = "A";
+    
+    /**
+     * Setzt den zu Beginn der Typinferenz auf "A" zurueck.
+     * Dies ist bei JUnit-Test noetig                       
+     * <code>TypePlaceholder</code>. <br>Author: Martin Pluemicke
+     * @return void
+     */
+    public static void reset() {
+    	strNextName = "A";
+    }
+    
+    /**
+     * Berechnet einen neuen, eindeutigen Namen f�r eine neue                          
+     * <code>TypePlaceholder</code>. <br>Author: J�rg B�uerle
+     * @return Der Name
+     */
+    public static String makeNewName()
+    {
+        // otth: Funktion berechnet einen neuen Namen anhand eines alten gespeicherten
+        String strReturn = strNextName;
+    
+        // n�chster Name berechnen und in strNextName speichern        
+        inc( strNextName.length() - 1 );
+
+        if (JavaTXServer.isRunning) {
+            throw new RuntimeException("Using the NameGenerator on a server is not allowed");
+        }
+        JavaTXCompiler.defaultClientPlaceholderRegistry.addPlaceholder(strReturn);
+        return strReturn;        
+    }
+
+    /**
+     * Hilfsfunktion zur Berechnung eines neuen Namens
+     * <br>Author: J�rg B�uerle
+     * @param i
+     */
+    private static void inc(int i)
+    {
+        // otth: Hilfsfunktion zur Berechnung eines neuen Namens
+        // otth: Erh�hung des Buchstabens an der Stelle i im String strNextName
+        // otth: Nach �berlauf: rekursiver Aufruf
+    
+        // falls i = -1 --> neuer Buchstabe vorne anf�gen
+        if ( i == -1 )
+        {
+            strNextName = "A" + strNextName;
+            return;
+        }
+    
+        char cBuchstabe = (char)(strNextName.charAt( i ));
+        cBuchstabe++;
+        if ( cBuchstabe - 65 > 25 )
+        {
+            // aktuelle Stelle: auf A zuruecksetzen
+            manipulate( i, 'A' );
+            
+            // vorherige Stelle erh�hen
+            inc( i - 1 );
+        }
+        else
+        {
+            // aktueller Buchstabe �ndern
+            manipulate( i, cBuchstabe );
+        }
+        
+    }
+
+    /**
+     * Hilfsfunktion zur Berechnung eines neuen Namens.
+     * <br>Author: J�rg B�uerle
+     * @param nStelle
+     * @param nWert
+     */
+    private static void manipulate( int nStelle, char nWert )
+    {
+        // otth: Hilfsfunktion zur Berechnung eines neuen Namens
+        // otth: Ersetzt im String 'strNextName' an der Position 'nStelle' den Buchstaben durch 'nWert'
+        
+        String strTemp = "";
+        for( int i = 0; i < strNextName.length(); i++)
+        {
+            if ( i == nStelle )
+                strTemp = strTemp + nWert;
+            else
+                strTemp = strTemp + strNextName.charAt( i );
+        }
+        strNextName = strTemp;
+    }
+    
+}

src/main/java/de/dhbwstuttgart/syntaxtree/factory/UnifyTypeFactory.java

@@ -1,6 +1,8 @@
 package de.dhbwstuttgart.syntaxtree.factory;
 
+import de.dhbwstuttgart.syntaxtree.SyntaxTree;
 import de.dhbwstuttgart.typeinference.unify.PlaceholderRegistry;
+import de.dhbwstuttgart.util.Logger;
 import java.io.Writer;
 import java.lang.reflect.Modifier;
 import java.util.*;
@@ -34,7 +36,7 @@ public class UnifyTypeFactory {
 	
     public static FiniteClosure generateFC(
       List<ClassOrInterface> fromClasses,
-      Writer logFile,
+      Logger logger,
       ClassLoader classLoader,
       JavaTXCompiler compiler,
       PlaceholderRegistry placeholderRegistry
@@ -49,7 +51,7 @@ public class UnifyTypeFactory {
         Generell dürfen sie immer die gleichen Namen haben.
         TODO: die transitive Hülle bilden
          */
-        return new FiniteClosure(FCGenerator.toUnifyFC(compiler, fromClasses, classLoader, placeholderRegistry), logFile, compiler, placeholderRegistry);
+        return new FiniteClosure(FCGenerator.toUnifyFC(compiler, fromClasses, classLoader, placeholderRegistry), logger, compiler, placeholderRegistry);
     }
 
     public static UnifyPair generateSmallerPair(UnifyType tl, UnifyType tr, SourceLoc location){
@@ -132,7 +134,7 @@ public class UnifyTypeFactory {
 
     public static UnifyType convert(JavaTXCompiler compiler, TypePlaceholder tph, Boolean innerType, PlaceholderRegistry placeholderRegistry) {
     	if (tph.getName().equals("AFR")) {
-    		System.out.println("XXX"+innerType);
+          SyntaxTree.logger.info("XXX"+innerType);
     	}
     	PlaceholderType ntph = new PlaceholderType(tph.getName(), tph.getVariance(), placeholderRegistry);
     	ntph.setVariance(tph.getVariance());
@@ -199,7 +201,7 @@ public class UnifyTypeFactory {
         		&& ((PlaceholderType)lhs).isWildcardable() 
         		&&	(rhs = ret.getLhsType()) instanceof PlaceholderType) {
         	if (lhs.getName().equals("AQ")) {
-        		// System.out.println("");
+        		// SyntaxTree.logger.info("");
         	}
         	((PlaceholderType)rhs).enableWildcardtable();
         }
@@ -208,7 +210,7 @@ public class UnifyTypeFactory {
         		&& ((PlaceholderType)rhs).isWildcardable()
         		&&	(lhs = ret.getLhsType()) instanceof PlaceholderType) {
         	if (rhs.getName().equals("AQ")) {
-        		// System.out.println("");
+        		// SyntaxTree.logger.info("");
         	}
         	((PlaceholderType)lhs).enableWildcardtable();
         }

src/main/java/de/dhbwstuttgart/syntaxtree/type/TypePlaceholder.java

@@ -7,6 +7,7 @@ import de.dhbwstuttgart.typeinference.unify.UnifyContext;
 
 import de.dhbwstuttgart.parser.NullToken;
 import de.dhbwstuttgart.syntaxtree.ASTVisitor;
+import de.dhbwstuttgart.syntaxtree.factory.NameGenerator;
 import de.dhbwstuttgart.typeinference.result.ResultSetVisitor;
 import org.antlr.v4.runtime.Token;
 
@@ -65,20 +66,16 @@ public class TypePlaceholder extends RefTypeOrTPHOrWildcardOrGeneric implements
      * @return
      */
     public static TypePlaceholder fresh(Token position){
-      return fresh(position, 0, true);
+		return new TypePlaceholder(NameGenerator.makeNewName(), position, 0, true);
     }
 
-    public static TypePlaceholder fresh(Token position, PlaceholderRegistry placeholderRegistry){
-      return fresh(position, 0, true, placeholderRegistry);
-    }
+  public static TypePlaceholder fresh(Token position, PlaceholderRegistry placeholderRegistry){
+    String newName = placeholderRegistry.generateFreshPlaceholderName();
+    return new TypePlaceholder(newName, position, 0, true);
+  }
 
     public static TypePlaceholder fresh(Token position, int variance, boolean wildcardable){
-      return fresh(position, variance, wildcardable, PlaceholderRegistry.defaultRegistry);
-    }
-
-    public static TypePlaceholder fresh(Token position, int variance, boolean wildcardable, PlaceholderRegistry placeholderRegistry){
-      String newName = placeholderRegistry.generateFreshPlaceholderName();
-		  return new TypePlaceholder(newName, position, variance, wildcardable);
+		return new TypePlaceholder(NameGenerator.makeNewName(), position, variance, wildcardable);
     }
 
     public static RefTypeOrTPHOrWildcardOrGeneric of(String name) {

src/main/java/de/dhbwstuttgart/target/Target.java

@@ -0,0 +1,8 @@
+package de.dhbwstuttgart.target;
+
+import de.dhbwstuttgart.util.Logger;
+
+public class Target {
+  public static Logger logger = new Logger("Target");
+
+}

src/main/java/de/dhbwstuttgart/target/generate/ASTToTargetAST.java

@@ -12,6 +12,7 @@ import de.dhbwstuttgart.syntaxtree.Record;
 import de.dhbwstuttgart.syntaxtree.factory.ASTFactory;
 import de.dhbwstuttgart.syntaxtree.statement.*;
 import de.dhbwstuttgart.syntaxtree.type.*;
+import de.dhbwstuttgart.target.Target;
 import de.dhbwstuttgart.target.tree.*;
 import de.dhbwstuttgart.target.tree.expression.*;
 import de.dhbwstuttgart.target.tree.type.*;
@@ -337,10 +338,10 @@ public class ASTToTargetAST {
 
         var result = r0.stream().map(l -> l.stream().toList()).toList();
 
-        System.out.println("============== OUTPUT ==============");
+        Target.logger.info("============== OUTPUT ==============");
         for (var l : result) {
-            for (var m : l) System.out.println(m.name() + " " + m.getSignature());
-            System.out.println();
+            for (var m : l) Target.logger.info(m.name() + " " + m.getSignature());
+            Target.logger.info("");
         }
         return result;
     }

src/main/java/de/dhbwstuttgart/target/generate/GenerateGenerics.java

@@ -1,10 +1,12 @@
 package de.dhbwstuttgart.target.generate;
 
+import de.dhbwstuttgart.core.JavaTXCompiler;
 import de.dhbwstuttgart.parser.NullToken;
 import de.dhbwstuttgart.syntaxtree.*;
 import de.dhbwstuttgart.syntaxtree.statement.*;
 import de.dhbwstuttgart.syntaxtree.type.*;
 import de.dhbwstuttgart.syntaxtree.type.Void;
+import de.dhbwstuttgart.target.Target;
 import de.dhbwstuttgart.target.tree.type.TargetGenericType;
 import de.dhbwstuttgart.target.tree.type.TargetType;
 import de.dhbwstuttgart.typeinference.result.PairTPHEqualTPH;
@@ -138,17 +140,17 @@ public abstract class GenerateGenerics {
         this.astToTargetAST = astToTargetAST;
         for (var constraint : constraints.results) {
             if (constraint instanceof PairTPHsmallerTPH p) {
-                System.out.println(p.left + " " + p.left.getVariance());
+                Target.logger.info(p.left + " " + p.left.getVariance());
                 simplifiedConstraints.add(new PairLT(new TPH(p.left), new TPH(p.right)));
             } else if (constraint instanceof PairTPHEqualTPH p) {
                 equality.put(p.getLeft(), p.getRight());
             } else if (constraint instanceof PairTPHequalRefTypeOrWildcardType p) {
-                System.out.println(p.left + " = " + p.right);
+                Target.logger.info(p.left + " = " + p.right);
                 concreteTypes.put(new TPH(p.left), p.right);
             }
         }
 
-        System.out.println("Simplified constraints: " + simplifiedConstraints);
+        Target.logger.info("Simplified constraints: " + simplifiedConstraints);
     }
 
     /*public record GenericsState(Map<TPH, RefTypeOrTPHOrWildcardOrGeneric> concreteTypes, Map<TypePlaceholder, TypePlaceholder> equality) {}
@@ -248,7 +250,7 @@ public abstract class GenerateGenerics {
                 equality.put(entry.getKey(), to);
             }
         }
-        System.out.println(from + " -> " + to + " " + from.getVariance());
+        Target.logger.info(from + " -> " + to + " " + from.getVariance());
         //from.setVariance(to.getVariance());
         equality.put(from, to);
         referenced.remove(new TPH(from));
@@ -317,7 +319,7 @@ public abstract class GenerateGenerics {
                     Set<TPH> T2s = new HashSet<>();
                     findTphs(superType, T2s);
 
-                    System.out.println("T1s: " + T1s + " T2s: " + T2s);
+                    Target.logger.info("T1s: " + T1s + " T2s: " + T2s);
                     //Ende
 
                     superType = methodCall.receiverType;
@@ -332,7 +334,7 @@ public abstract class GenerateGenerics {
                             var optMethod = astToTargetAST.findMethod(owner, methodCall.name, methodCall.signatureArguments().stream().map(astToTargetAST::convert).toList());
                             if (optMethod.isEmpty()) return;
                             var method2 = optMethod.get();
-                            System.out.println("In: " + method.getName() + " Method: " + method2.getName());
+                            Target.logger.info("In: " + method.getName() + " Method: " + method2.getName());
                             var generics = family(owner, method2);
 
                             // transitive and
@@ -365,7 +367,7 @@ public abstract class GenerateGenerics {
                                                     if (!T1s.contains(R1) || !T2s.contains(R2)) continue;
 
                                                     var newPair = new PairLT(R1, R2);
-                                                    System.out.println("New pair: " + newPair);
+                                                    Target.logger.info("New pair: " + newPair);
                                                     newPairs.add(newPair);
 
                                                     if (!containsRelation(result, newPair))
@@ -567,7 +569,7 @@ public abstract class GenerateGenerics {
     Set<Pair> generics(ClassOrInterface owner, Method method) {
         if (computedGenericsOfMethods.containsKey(method)) {
             var cached = computedGenericsOfMethods.get(method);
-            System.out.println("Cached " + method.getName() + ": " + cached);
+            Target.logger.info("Cached " + method.getName() + ": " + cached);
             return cached;
         }
 
@@ -596,7 +598,7 @@ public abstract class GenerateGenerics {
 
         normalize(result, classGenerics, usedTphs);
 
-        System.out.println(this.getClass().getSimpleName() + " " + method.name + ": " + result);
+        Target.logger.info(this.getClass().getSimpleName() + " " + method.name + ": " + result);
         return result;
     }
 
@@ -675,7 +677,7 @@ public abstract class GenerateGenerics {
 
         normalize(javaResult, null, referencedByClass);
 
-        System.out.println(this.getClass().getSimpleName() + " Class " + classOrInterface.getClassName().getClassName() + ": " + javaResult);
+        Target.logger.info(this.getClass().getSimpleName() + " Class " + classOrInterface.getClassName().getClassName() + ": " + javaResult);
         return javaResult;
     }
 
@@ -726,7 +728,7 @@ public abstract class GenerateGenerics {
                     if (!added) break;
                 }
 
-                System.out.println(chain + " " + chain.stream().map(e -> e.resolve().getVariance()).toList());
+                Target.logger.info(chain + " " + chain.stream().map(e -> e.resolve().getVariance()).toList());
                 var variance = chain.get(0).resolve().getVariance();
                 if (variance != 1) continue;
                 var index = 0;
@@ -764,7 +766,7 @@ public abstract class GenerateGenerics {
         }
 
         for (var pair : elementsToAddToEquality) {
-            System.out.println(pair);
+            Target.logger.info(pair);
             addToEquality(pair.left, pair.right, referenced);
         }
     }
@@ -917,11 +919,11 @@ public abstract class GenerateGenerics {
                     }
                 }
                 if (infima.size() > 1) {
-                    System.out.println(infima);
+                    Target.logger.info(infima);
                     for (var pair : infima) {
                         var returnTypes = findTypeVariables(method.getReturnType());
                         var chain = findConnectionToReturnType(returnTypes, input, new HashSet<>(), pair.left);
-                        System.out.println("Find: " + pair.left + " " + chain);
+                        Target.logger.info("Find: " + pair.left + " " + chain);
                         chain.remove(pair.left);
                         if (chain.size() > 0) {
                             for (var tph : chain)
@@ -959,8 +961,8 @@ public abstract class GenerateGenerics {
                         }
                     }
                     newTph.setVariance(variance);
-                    System.out.println(infima + " " + infima.stream().map(i -> i.right.resolve().getVariance()).toList());
-                    System.out.println("Infima new TPH " + newTph + " variance " + variance);
+                    Target.logger.info(infima + " " + infima.stream().map(i -> i.right.resolve().getVariance()).toList());
+                    Target.logger.info("Infima new TPH " + newTph + " variance " + variance);
 
                     //referenced.add(newTph);
                     addToPairs(input, new PairLT(left, new TPH(newTph)));

src/main/java/de/dhbwstuttgart/target/generate/StatementToTargetExpression.java

@@ -8,6 +8,7 @@ import de.dhbwstuttgart.parser.scope.JavaClassName;
 import de.dhbwstuttgart.syntaxtree.*;
 import de.dhbwstuttgart.syntaxtree.statement.*;
 import de.dhbwstuttgart.syntaxtree.type.*;
+import de.dhbwstuttgart.target.Target;
 import de.dhbwstuttgart.target.tree.MethodParameter;
 import de.dhbwstuttgart.target.tree.TargetMethod;
 import de.dhbwstuttgart.target.tree.expression.*;
@@ -120,7 +121,7 @@ public class StatementToTargetExpression implements ASTVisitor {
 
     @Override
     public void visit(BoolExpression bool) {
-        System.out.println("BoolExpression");
+        Target.logger.info("BoolExpression");
     }
 
     @Override
@@ -234,7 +235,7 @@ public class StatementToTargetExpression implements ASTVisitor {
             isInterface = receiverClass.isInterface();
         }
 
-        System.out.println(argList);
+        Target.logger.info(argList);
         result = new TargetMethodCall(converter.convert(methodCall.getType()), returnType, argList, converter.convert(methodCall.receiver), methodCall.getArgumentList().getArguments().stream().map(converter::convert).toList(), receiverType, methodCall.name, isStatic, isInterface, isPrivate);
     }
 

src/main/java/de/dhbwstuttgart/typeinference/assumptions/FunNClass.java

@@ -7,6 +7,7 @@ import de.dhbwstuttgart.syntaxtree.GenericDeclarationList;
 import de.dhbwstuttgart.syntaxtree.GenericTypeVar;
 import de.dhbwstuttgart.syntaxtree.Method;
 import de.dhbwstuttgart.syntaxtree.factory.ASTFactory;
+import de.dhbwstuttgart.syntaxtree.factory.NameGenerator;
 import de.dhbwstuttgart.syntaxtree.type.GenericRefType;
 
 

src/main/java/de/dhbwstuttgart/typeinference/assumptions/MethodAssumption.java

@@ -19,11 +19,11 @@ public class MethodAssumption extends Assumption{
     private ClassOrInterface receiver;
     private RefTypeOrTPHOrWildcardOrGeneric retType;
     List<? extends RefTypeOrTPHOrWildcardOrGeneric> params;
-    private final Boolean isInherited;
-    private final Boolean isOverridden;
+    private final boolean isInherited;
+    private final boolean isOverridden;
 
     public MethodAssumption(ClassOrInterface receiver, RefTypeOrTPHOrWildcardOrGeneric retType,
-                            List<? extends RefTypeOrTPHOrWildcardOrGeneric> params, TypeScope scope, Boolean isInherited, Boolean isOverridden){
+                            List<? extends RefTypeOrTPHOrWildcardOrGeneric> params, TypeScope scope, boolean isInherited, boolean isOverridden){
         super(scope);
         this.receiver = receiver;
         this.retType = retType;
@@ -73,11 +73,11 @@ public class MethodAssumption extends Assumption{
         return TYPEStmt.getReceiverType(receiver, resolver);
     }
     
-    public Boolean isInherited() {
+    public boolean isInherited() {
     	return isInherited;
     }
     
-    public Boolean isOverridden() {
+    public boolean isOverridden() {
     	return isOverridden;
     }
 }

src/main/java/de/dhbwstuttgart/typeinference/constraints/Constraint.java

@@ -22,8 +22,8 @@ import javax.annotation.Nullable;
 
 public class Constraint<A extends IConstraintElement> extends HashSet<A> implements ISerializableData {
   private static final long serialVersionUID = 1L;
-  private Boolean isInherited = false;//wird beides nur für die Method-Constraints benoetigt
-  private Boolean isImplemented = false;
+  private boolean isInherited = false;//wird beides nur für die Method-Constraints benoetigt
+  private boolean isImplemented = false;
 
   /*
    * wird verwendet um bei der Codegenerierung die richtige Methoden - Signatur
@@ -37,27 +37,31 @@ public class Constraint<A extends IConstraintElement> extends HashSet<A> impleme
     super();
   }
 
-  public Constraint(Boolean isInherited, Boolean isImplemented) {
+  public Constraint(int initialCapacity) {
+    super(initialCapacity);
+  }
+
+  public Constraint(boolean isInherited, boolean isImplemented) {
     this.isInherited = isInherited;
     this.isImplemented = isImplemented;
   }
 
-  public Constraint(Boolean isInherited, Boolean isImplemented, Constraint<A> extendConstraint, Set<A> methodSignatureConstraint) {
+  public Constraint(boolean isInherited, boolean isImplemented, Constraint<A> extendConstraint, Set<A> methodSignatureConstraint) {
     this.isInherited = isInherited;
     this.isImplemented = isImplemented;
     this.extendConstraint = extendConstraint;
     this.methodSignatureConstraint = methodSignatureConstraint;
   }
 
-  public void setIsInherited(Boolean isInherited) {
+  public void setIsInherited(boolean isInherited) {
     this.isInherited = isInherited;
   }
 
-  public Boolean isInherited() {
+  public boolean isInherited() {
     return isInherited;
   }
 
-  public Boolean isImplemented() {
+  public boolean isImplemented() {
     return isImplemented;
   }
 
@@ -77,6 +81,14 @@ public class Constraint<A extends IConstraintElement> extends HashSet<A> impleme
     methodSignatureConstraint = c;
   }
 
+  public <B extends IConstraintElement> Constraint<B> createdMapped(Function<A,B> mapper) {
+    Constraint<B> result = new Constraint<>(this.size());
+    for (A element : this) {
+      result.add(mapper.apply(element));
+    }
+    return result;
+  }
+
   public String toString() {
     return super.toString() + "\nisInherited = " + isInherited
       + " isOveridden = " + isImplemented

src/main/java/de/dhbwstuttgart/typeinference/constraints/Pair.java

@@ -21,7 +21,7 @@ public class Pair implements Serializable, IConstraintElement, ISerializableData
   private SourceLoc location;
 
   private PairOperator eOperator = PairOperator.SMALLER;
-  private Boolean noUnification = false;
+  private boolean noUnification = false;
 
 
   private Pair(RefTypeOrTPHOrWildcardOrGeneric TA1, RefTypeOrTPHOrWildcardOrGeneric TA2) {
@@ -43,7 +43,7 @@ public class Pair implements Serializable, IConstraintElement, ISerializableData
     this.location = location;
   }
 
-  public Pair(RefTypeOrTPHOrWildcardOrGeneric TA1, RefTypeOrTPHOrWildcardOrGeneric TA2, PairOperator eOp, Boolean noUnification) {
+  public Pair(RefTypeOrTPHOrWildcardOrGeneric TA1, RefTypeOrTPHOrWildcardOrGeneric TA2, PairOperator eOp, boolean noUnification) {
     // Konstruktor
     this(TA1, TA2);
     this.eOperator = eOp;
@@ -161,7 +161,7 @@ public class Pair implements Serializable, IConstraintElement, ISerializableData
     String op = data.getValue("op").getOf(String.class);
     SerialMap ta1 = data.getMap("ta1");
     SerialMap ta2 = data.getMap("ta2");
-    Boolean noUnification = data.getValue("noUnification").getOf(Integer.class) == 1;
+    boolean noUnification = data.getValue("noUnification").getOf(Integer.class) == 1;
     SerialMap location = data.getMapOrNull("location");
 
     var pair = new Pair(

src/main/java/de/dhbwstuttgart/typeinference/result/PairNoResult.java

@@ -38,7 +38,7 @@ implements ISerializableData {
     public SerialMap toSerial(KeyStorage keyStorage) {
         SerialMap serialized = new SerialMap();
         serialized.put("left", this.getLeft().toSerial(keyStorage));
-        serialized.put("right", this.getLeft().toSerial(keyStorage));
+        serialized.put("right", this.getRight().toSerial(keyStorage));
         // create the wrapper and put this as the object
         var serializedWrapper = super.toSerial(keyStorage);
         serializedWrapper.put("object", serialized);

src/main/java/de/dhbwstuttgart/typeinference/result/PairTPHEqualTPH.java

@@ -21,7 +21,7 @@ public class PairTPHEqualTPH extends ResultPair<TypePlaceholder, TypePlaceholder
     public SerialMap toSerial(KeyStorage keyStorage) {
         SerialMap serialized = new SerialMap();
         serialized.put("left", this.getLeft().toSerial(keyStorage));
-        serialized.put("right", this.getLeft().toSerial(keyStorage));
+        serialized.put("right", this.getRight().toSerial(keyStorage));
         // create the wrapper and put this as the object
         var serializedWrapper = super.toSerial(keyStorage);
         serializedWrapper.put("object", serialized);

src/main/java/de/dhbwstuttgart/typeinference/result/PairTPHsmallerTPH.java

@@ -46,7 +46,7 @@ public class PairTPHsmallerTPH extends ResultPair<TypePlaceholder,TypePlaceholde
     public SerialMap toSerial(KeyStorage keyStorage) {
         SerialMap serialized = new SerialMap();
         serialized.put("left", this.getLeft().toSerial(keyStorage));
-        serialized.put("right", this.getLeft().toSerial(keyStorage));
+        serialized.put("right", this.getRight().toSerial(keyStorage));
         // create the wrapper and put this as the object
         var serializedWrapper = super.toSerial(keyStorage);
         serializedWrapper.put("object", serialized);

src/main/java/de/dhbwstuttgart/typeinference/result/ResultSet.java

@@ -5,8 +5,11 @@ import de.dhbwstuttgart.server.packet.dataContainers.ISerializableData;
 import de.dhbwstuttgart.server.packet.dataContainers.KeyStorage;
 import de.dhbwstuttgart.server.packet.dataContainers.serialized.SerialList;
 import de.dhbwstuttgart.server.packet.dataContainers.serialized.SerialMap;
+import de.dhbwstuttgart.typeinference.unify.TypeUnifyTaskHelper;
 import de.dhbwstuttgart.typeinference.unify.UnifyContext;
+import de.dhbwstuttgart.util.Logger;
 import java.util.ArrayList;
+import java.util.Comparator;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -27,7 +30,7 @@ public class ResultSet implements ISerializableData {
 
   public ResultSet(Set<ResultPair> set) {
     this.results = set;
-    this.genIns = new HashSet<>();
+    this.genIns = TypeUnifyTaskHelper.getPresizedHashSet(results.size());
     results.forEach(x -> {
       if (x instanceof PairTPHsmallerTPH) {
         this.genIns.add(x);
@@ -59,15 +62,19 @@ public class ResultSet implements ISerializableData {
 
   public String toString() {
     var results = new ArrayList<>(this.results);
-    results.sort(Ordering.usingToString());
+    results.sort(
+      Comparator
+        .comparingInt((ResultPair o) -> o.getLeft().toString().length())
+        .thenComparing(o -> o.getLeft().toString())
+        .thenComparingInt(o -> o.getRight().toString().length())
+        .thenComparing(o -> o.getRight().toString())
+    );
     return results.toString();
   }
 
   @Override
   public boolean equals(Object o) {
-    if (o instanceof ResultSet) {
-      ResultSet other = (ResultSet) o;
-
+    if (o instanceof ResultSet other) {
       // sort both result lists
       var thisElements = new ArrayList<>(this.results);
       thisElements.sort(Ordering.usingToString());
@@ -105,6 +112,8 @@ class Resolver implements ResultSetVisitor {
   private final Set<GenericInsertPair> additionalTPHs = new HashSet<>();
   private ResultPair<?, ?> currentPair;
 
+  public static Logger logger = new Logger("Resolver");
+
   public Resolver(ResultSet resultPairs) {
     this.result = resultPairs;
   }
@@ -112,7 +121,7 @@ class Resolver implements ResultSetVisitor {
   public ResolvedType resolve(TypePlaceholder tph) {
     toResolve = tph;
     resolved = null;
-    System.out.println(tph.toString());
+    logger.info(tph.toString());
     for (ResultPair<?, ?> resultPair : result.results) {
       if (resultPair instanceof PairTPHEqualTPH && ((PairTPHEqualTPH) resultPair).getLeft().equals(toResolve)) {
         currentPair = resultPair;

src/main/java/de/dhbwstuttgart/typeinference/typeAlgo/TYPE.java

@@ -14,6 +14,7 @@ import de.dhbwstuttgart.typeinference.assumptions.TypeInferenceBlockInformation;
 import de.dhbwstuttgart.typeinference.assumptions.TypeInferenceInformation;
 import de.dhbwstuttgart.typeinference.constraints.ConstraintSet;
 import de.dhbwstuttgart.typeinference.constraints.Pair;
+import de.dhbwstuttgart.typeinference.unify.TypeUnifyTaskHelper;
 import de.dhbwstuttgart.typeinference.unify.model.PairOperator;
 import de.dhbwstuttgart.util.BiRelation;
 import org.antlr.v4.runtime.Token;
@@ -33,7 +34,7 @@ public class TYPE {
     public ConstraintSet getConstraints() {
         ConstraintSet ret = new ConstraintSet();
         for (ClassOrInterface cl : sf.KlassenVektor) {
-            var allClasses = new HashSet<ClassOrInterface>();
+            Set<ClassOrInterface> allClasses = TypeUnifyTaskHelper.getPresizedHashSet(allAvailableClasses.size() + sf.availableClasses.size());
             allClasses.addAll(allAvailableClasses);
             allClasses.addAll(sf.availableClasses);
             ret.addAll(getConstraintsClass(cl, new TypeInferenceInformation(allClasses)));
@@ -68,7 +69,7 @@ public class TYPE {
 
             for(SourceFile sourceFile : sfs){
                 for(JavaClassName importName : sourceFile.imports){
-                    System.out.println(importName);
+                    context.logger().info(importName);
                     try {
                         classes.add(ASTFactory.createClass(classLoader.loadClass(importName.toString())));
                     } catch (ClassNotFoundException e) {

src/main/java/de/dhbwstuttgart/typeinference/typeAlgo/TYPEStmt.java

@@ -2,6 +2,7 @@
 package de.dhbwstuttgart.typeinference.typeAlgo;
 
 import de.dhbwstuttgart.typeinference.unify.PlaceholderRegistry;
+import de.dhbwstuttgart.typeinference.unify.TypeUnifyTaskHelper;
 import java.util.*;
 import java.util.stream.Collectors;
 
@@ -13,6 +14,7 @@ import de.dhbwstuttgart.parser.SyntaxTreeGenerator.AssignToLocal;
 import de.dhbwstuttgart.parser.scope.JavaClassName;
 import de.dhbwstuttgart.syntaxtree.*;
 import de.dhbwstuttgart.syntaxtree.factory.ASTFactory;
+import de.dhbwstuttgart.syntaxtree.factory.NameGenerator;
 import de.dhbwstuttgart.syntaxtree.statement.*;
 import de.dhbwstuttgart.syntaxtree.type.ExtendsWildcardType;
 import de.dhbwstuttgart.syntaxtree.type.GenericRefType;
@@ -116,17 +118,18 @@ public class TYPEStmt implements StatementVisitor {
     @Override
     public void visit(FieldVar fieldVar) {
         fieldVar.receiver.accept(this);
-        Set<Constraint> oderConstraints = new HashSet<>();
+        List<FieldAssumption> fieldAssumptions = info.getFields(fieldVar.fieldVarName);
+        Set<Constraint> oderConstraints = TypeUnifyTaskHelper.getPresizedHashSet(fieldAssumptions.size());
 
 
-        for (FieldAssumption fieldAssumption : info.getFields(fieldVar.fieldVarName)) {
+        for (FieldAssumption fieldAssumption : fieldAssumptions) {
             Constraint constraint = new Constraint();
             GenericsResolver resolver = getResolverInstance();
             constraint.add(new Pair(fieldVar.receiver.getType(), fieldAssumption.getReceiverType(resolver), PairOperator.SMALLERDOT, loc(fieldVar.getOffset()))); // PL 2019-12-09: SMALLERDOT eingefuegt, EQUALSDOT entfernt, wenn ds Field privat ist muesste es EQUALSDOT lauten
             constraint.add(new Pair(fieldVar.getType(), fieldAssumption.getType(resolver), PairOperator.EQUALSDOT, loc(fieldVar.getOffset())));
             oderConstraints.add(constraint);
         }
-        if (oderConstraints.size() == 0)
+        if (oderConstraints.isEmpty())
             throw new TypeinferenceException("Kein Feld " + fieldVar.fieldVarName + " gefunden", fieldVar.getOffset());
         constraintsSet.addOderConstraint(oderConstraints);
     }
@@ -141,7 +144,7 @@ public class TYPEStmt implements StatementVisitor {
 
     @Override
     public void visit(ForEachStmt forEachStmt) {
-        var iterableType = new RefType(ASTFactory.createClass(java.lang.Iterable.class).getClassName(), Arrays.asList(new ExtendsWildcardType(forEachStmt.statement.getType(), new NullToken())), new NullToken());
+        var iterableType = new RefType(ASTFactory.createClass(java.lang.Iterable.class).getClassName(), List.of(new ExtendsWildcardType(forEachStmt.statement.getType(), new NullToken())), new NullToken());
         constraintsSet.addUndConstraint(new Pair(forEachStmt.expression.getType(), iterableType, PairOperator.SMALLERDOT, loc(forEachStmt.getOffset())));
         forEachStmt.statement.accept(this);
         forEachStmt.expression.accept(this);
@@ -189,7 +192,7 @@ public class TYPEStmt implements StatementVisitor {
         methodCall.receiver.accept(this);
         // Overloading:
         Set<Constraint<Pair>> methodConstraints = new HashSet<>();
-        for (MethodAssumption m : this.getMethods(methodCall.name, methodCall.arglist, info)) {
+        for (MethodAssumption m : TYPEStmt.getMethods(methodCall.name, methodCall.arglist, info)) {
             GenericsResolver resolver = getResolverInstance();
             Set<Constraint<Pair>> oneMethodConstraints = generateConstraint(methodCall, m, info, resolver);
             methodConstraints.addAll(oneMethodConstraints);
@@ -199,7 +202,7 @@ public class TYPEStmt implements StatementVisitor {
              * oneMethodConstraint.setExtendConstraint(extendsOneMethodConstraint); extendsOneMethodConstraint.setExtendConstraint(oneMethodConstraint); methodConstraints.add(extendsOneMethodConstraint);
              */
         }
-        if (methodConstraints.size() < 1) {
+        if (methodConstraints.isEmpty()) {
             throw new TypeinferenceException("Methode " + methodCall.name + " ist nicht vorhanden!", methodCall.getOffset());
         }
         constraintsSet.addOderConstraint(methodConstraints);
@@ -212,7 +215,7 @@ public class TYPEStmt implements StatementVisitor {
         for (MethodAssumption m : this.getConstructors(info, (RefType) methodCall.getType(), methodCall.getArgumentList())) {
             methodConstraints.add(generateConstructorConstraint(methodCall, m, info, getResolverInstance()));
         }
-        if (methodConstraints.size() < 1) {
+        if (methodConstraints.isEmpty()) {
             throw new TypeinferenceException("Konstruktor in Klasse " + methodCall.getType().toString() + " ist nicht vorhanden!", methodCall.getOffset());
         }
         constraintsSet.addOderConstraint(methodConstraints);
@@ -282,8 +285,13 @@ public class TYPEStmt implements StatementVisitor {
             // see: https://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.17
             // Expression muss zu Numeric Convertierbar sein. also von Numeric erben
             Constraint<Pair> numeric;
+            HashSet<JavaClassName> classNames = TypeUnifyTaskHelper.getPresizedHashSet(info.getAvailableClasses().size());
+            for (var classEl : info.getAvailableClasses()) {
+                classNames.add(classEl.getClassName());
+            }
+
             // PL eingefuegt 2018-07-17
-            if (info.getAvailableClasses().stream().map(x -> x.getClassName()).collect(Collectors.toCollection(HashSet::new)).contains(bytee.getName())) {
+            if (classNames.contains(bytee.getName())) {
                 numeric = new Constraint<>();
                 numeric.add(new Pair(binary.lexpr.getType(), bytee, PairOperator.SMALLERDOT, loc(binary.getOffset())));
                 numeric.add(new Pair(binary.rexpr.getType(), bytee, PairOperator.SMALLERDOT, loc(binary.getOffset())));
@@ -291,7 +299,7 @@ public class TYPEStmt implements StatementVisitor {
                 numericAdditionOrStringConcatenation.add(numeric);
             }
             // PL eingefuegt 2018-07-17
-            if (info.getAvailableClasses().stream().map(x -> x.getClassName()).collect(Collectors.toCollection(HashSet::new)).contains(shortt.getName())) {
+            if (classNames.contains(shortt.getName())) {
                 numeric = new Constraint<>();
                 numeric.add(new Pair(binary.lexpr.getType(), shortt, PairOperator.SMALLERDOT, loc(binary.getOffset())));
                 numeric.add(new Pair(binary.rexpr.getType(), shortt, PairOperator.SMALLERDOT, loc(binary.getOffset())));
@@ -299,7 +307,7 @@ public class TYPEStmt implements StatementVisitor {
                 numericAdditionOrStringConcatenation.add(numeric);
             }
             // PL eingefuegt 2018-07-17
-            if (info.getAvailableClasses().stream().map(x -> x.getClassName()).collect(Collectors.toCollection(HashSet::new)).contains(integer.getName())) {
+            if (classNames.contains(integer.getName())) {
                 numeric = new Constraint<>();
                 numeric.add(new Pair(binary.lexpr.getType(), integer, PairOperator.SMALLERDOT, loc(binary.getOffset())));
                 numeric.add(new Pair(binary.rexpr.getType(), integer, PairOperator.SMALLERDOT, loc(binary.getOffset())));
@@ -307,7 +315,7 @@ public class TYPEStmt implements StatementVisitor {
                 numericAdditionOrStringConcatenation.add(numeric);
             }
             // PL eingefuegt 2018-07-17
-            if (info.getAvailableClasses().stream().map(x -> x.getClassName()).collect(Collectors.toCollection(HashSet::new)).contains(longg.getName())) {
+            if (classNames.contains(longg.getName())) {
                 numeric = new Constraint<>();
                 numeric.add(new Pair(binary.lexpr.getType(), longg, PairOperator.SMALLERDOT, loc(binary.getOffset())));
                 numeric.add(new Pair(binary.rexpr.getType(), longg, PairOperator.SMALLERDOT, loc(binary.getOffset())));
@@ -315,7 +323,7 @@ public class TYPEStmt implements StatementVisitor {
                 numericAdditionOrStringConcatenation.add(numeric);
             }
             // PL eingefuegt 2018-07-17
-            if (info.getAvailableClasses().stream().map(x -> x.getClassName()).collect(Collectors.toCollection(HashSet::new)).contains(floatt.getName())) {
+            if (classNames.contains(floatt.getName())) {
                 numeric = new Constraint<>();
                 numeric.add(new Pair(binary.lexpr.getType(), floatt, PairOperator.SMALLERDOT, loc(binary.getOffset())));
                 numeric.add(new Pair(binary.rexpr.getType(), floatt, PairOperator.SMALLERDOT, loc(binary.getOffset())));
@@ -323,7 +331,7 @@ public class TYPEStmt implements StatementVisitor {
                 numericAdditionOrStringConcatenation.add(numeric);
             }
             // PL eingefuegt 2018-07-17
-            if (info.getAvailableClasses().stream().map(x -> x.getClassName()).collect(Collectors.toCollection(HashSet::new)).contains(doublee.getName())) {
+            if (classNames.contains(doublee.getName())) {
                 numeric = new Constraint<>();
                 numeric.add(new Pair(binary.lexpr.getType(), doublee, PairOperator.SMALLERDOT, loc(binary.getOffset())));
                 numeric.add(new Pair(binary.rexpr.getType(), doublee, PairOperator.SMALLERDOT, loc(binary.getOffset())));
@@ -338,7 +346,7 @@ public class TYPEStmt implements StatementVisitor {
 
             if (binary.operation.equals(BinaryExpr.Operator.ADD)) {
                 // Dann kann der Ausdruck auch das aneinanderfügen zweier Strings sein: ("a" + "b") oder (1 + 2)
-                if (info.getAvailableClasses().stream().map(x -> x.getClassName()).collect(Collectors.toCollection(HashSet::new)).contains(string.getName())) {
+                if (classNames.contains(string.getName())) {
                     Constraint<Pair> stringConcat = new Constraint<>();
                     stringConcat.add(new Pair(binary.lexpr.getType(), string, PairOperator.EQUALSDOT, loc(binary.getOffset())));
                     stringConcat.add(new Pair(binary.rexpr.getType(), string, PairOperator.EQUALSDOT, loc(binary.getOffset())));
@@ -346,7 +354,7 @@ public class TYPEStmt implements StatementVisitor {
                     numericAdditionOrStringConcatenation.add(stringConcat);
                 }
             }
-            if (numericAdditionOrStringConcatenation.size() < 1) {
+            if (numericAdditionOrStringConcatenation.isEmpty()) {
                 throw new TypeinferenceException("Kein Typ für " + binary.operation.toString() + " vorhanden", binary.getOffset());
             }
             constraintsSet.addOderConstraint(numericAdditionOrStringConcatenation);
@@ -693,8 +701,8 @@ public class TYPEStmt implements StatementVisitor {
 
         Set<Pair> methodSignatureConstraint = generatemethodSignatureConstraint(forMethod, assumption, info, resolver);
 
-        //System.out.println("methodSignatureConstraint: " + methodSignatureConstraint);
-        //System.out.println("methodConstraint: " + methodConstraint);
+        //context.logger().info("methodSignatureConstraint: " + methodSignatureConstraint);
+        //context.logger().info("methodConstraint: " + methodConstraint);
 
         methodConstraint.setmethodSignatureConstraint(methodSignatureConstraint);
         extendsMethodConstraint.setmethodSignatureConstraint(methodSignatureConstraint);
@@ -732,7 +740,7 @@ public class TYPEStmt implements StatementVisitor {
         }
 
         // Zuordnung von MethodCall.signature(ReturnType) zu dem ReturnType der ausgewaehlten Methode (assumption.returnType)
-        ret.add(new Pair(foMethod.signature.get(foMethod.signature.size() - 1), assumption.getReturnType(), PairOperator.EQUALSDOT));
+        ret.add(new Pair(foMethod.signature.getLast(), assumption.getReturnType(), PairOperator.EQUALSDOT));
         return ret;
     }
 
@@ -743,10 +751,10 @@ public class TYPEStmt implements StatementVisitor {
             List<GenericRefType> funNParams = new ArrayList<>();
             for (int i = 0; i < numArgs + 1; i++) {
                 // funNParams.add(TypePlaceholder.fresh(new NullToken()));
-                funNParams.add(new GenericRefType(PlaceholderRegistry.defaultRegistry.generateFreshPlaceholderName(), new NullToken()));
+                funNParams.add(new GenericRefType(NameGenerator.makeNewName(), new NullToken()));
             }
-            funNParams.get(funNParams.size() - 1);
-            ret.add(new MethodAssumption(new FunNClass(funNParams), funNParams.get(funNParams.size() - 1), funNParams.subList(0, funNParams.size() - 1), new TypeScope() {
+            funNParams.getLast();
+            ret.add(new MethodAssumption(new FunNClass(funNParams), funNParams.getLast(), funNParams.subList(0, funNParams.size() - 1), new TypeScope() {
                 @Override
                 public Iterable<? extends GenericTypeVar> getGenerics() {
                     throw new NotImplementedException();
@@ -841,7 +849,7 @@ public class TYPEStmt implements StatementVisitor {
             for (var child : switchStmt.getBlocks()) {
                 for (var label : child.getLabels()) {
                     if (label.getPattern() == null) {
-                        //System.out.println("DefaultCase");
+                        //context.logger().info("DefaultCase");
                     } else {
                         constraintsSet.addUndConstraint(
                                 new Pair(
@@ -882,13 +890,9 @@ public class TYPEStmt implements StatementVisitor {
 
             child.getLabels().forEach(el -> {
                 if (el.getType() instanceof RefType) {
-                    var recType = el;
-
-                    if (el.getPattern() instanceof RecordPattern) {
-                        var pattern = (RecordPattern) recType.getPattern();
-                        recursivelyAddRecordConstraints(pattern);
-                    }
-
+                  if (el.getPattern() instanceof RecordPattern pattern) {
+                    recursivelyAddRecordConstraints(pattern);
+                  }
                 }
             });
 
@@ -904,13 +908,13 @@ public class TYPEStmt implements StatementVisitor {
 
         var allClasses = info.getAvailableClasses();
         var interestingClasses = allClasses.stream().filter(as -> as.getClassName().equals(((RefType) pattern.getType()).getName())).toList();
-        var constructors = interestingClasses.get(0).getConstructors();
+        var constructors = interestingClasses.getFirst().getConstructors();
 
         int counter = 0;
 
         for (var subPattern : pattern.getSubPattern()) {
             for (Constructor con : constructors) {
-                //System.out.println("----------------------\n" + subPattern.getType() + " | " + con.getParameterList().getParameterAt(counter).getType() + "\n----------------------\n");
+                //context.logger().info("----------------------\n" + subPattern.getType() + " | " + con.getParameterList().getParameterAt(counter).getType() + "\n----------------------\n");
                 constraintsSet.addUndConstraint(new Pair(subPattern.getType(), con.getParameterList().getParameterAt(counter).getType(), PairOperator.SMALLERDOT, loc(con.getParameterList().getParameterAt(counter).getOffset())));
             }
             if (subPattern instanceof RecordPattern) recursivelyAddRecordConstraints((RecordPattern) subPattern);

src/main/java/de/dhbwstuttgart/typeinference/unify/ConcurrentSetMergeTask.java

@@ -37,9 +37,6 @@ public class ConcurrentSetMergeTask<T> extends RecursiveTask<Set<T>> {
       totalElements += list.get(i).size();
     }
 
-    System.out.println("ConcurrentSetMerge? -> " + (size <= LIST_THRESHOLD || totalElements < ELEMENT_THRESHOLD ? "true" : "false"));
-
-
     // size will always be at least one
     if (true || size <= LIST_THRESHOLD || totalElements < ELEMENT_THRESHOLD) {
       Set<T> result = this.list.get(start);

src/main/java/de/dhbwstuttgart/typeinference/unify/MartelliMontanariUnify.java

@@ -95,7 +95,7 @@ public class MartelliMontanariUnify implements IUnify {
 			if(lhsType instanceof PlaceholderType) {
 				mgu.add((PlaceholderType) lhsType, rhsType);
 				//PL 2018-04-01 nach checken, ob es richtig ist, dass keine Substitutionen uebergeben werden muessen.
-				termsList = termsList.stream().map(x -> mgu.apply(x)).collect(Collectors.toCollection(ArrayList::new));
+				termsList.replaceAll(mgu::apply);
 				idx = idx+1 == termsList.size() ? 0 : idx+1;
 				continue;
 			}

src/main/java/de/dhbwstuttgart/typeinference/unify/PlaceholderRegistry.java

@@ -16,10 +16,6 @@ import java.util.concurrent.atomic.AtomicInteger;
  */
 public class PlaceholderRegistry implements ISerializableData {
 
-  // The default registry should only ever be used outside on the Client-Side and NEVER on the Server-Side!
-  // This includes at least the server-handled packets and the unification algorithm
-  public static PlaceholderRegistry defaultRegistry = new PlaceholderRegistry();
-
   private final Set<String> existingPlaceholders = ConcurrentHashMap.newKeySet();
   private final AtomicInteger placeholderCount = new AtomicInteger();
   public ArrayList<PlaceholderType> UnifyTypeFactory_PLACEHOLDERS = new ArrayList<>();
@@ -49,6 +45,14 @@ public class PlaceholderRegistry implements ISerializableData {
     return name;
   }
 
+  public PlaceholderRegistry deepClone() {
+    PlaceholderRegistry pr2 = new PlaceholderRegistry();
+    this.existingPlaceholders.forEach(pr2::addPlaceholder);
+    pr2.UnifyTypeFactory_PLACEHOLDERS.addAll(this.UnifyTypeFactory_PLACEHOLDERS);
+    pr2.placeholderCount.set(this.placeholderCount.get());
+    return pr2;
+  }
+
   /**
    * Generate a token that consists of uppercase letters and contains the given prefix and suffix from the value i
    *

src/main/java/de/dhbwstuttgart/typeinference/unify/RuleSet.java

@@ -1,10 +1,12 @@
 package de.dhbwstuttgart.typeinference.unify;
 
+import de.dhbwstuttgart.util.Logger;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.ListIterator;
 import java.util.Optional;
 import java.util.Queue;
 import java.util.Set;
@@ -12,24 +14,16 @@ import java.util.Stack;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
-import de.dhbwstuttgart.core.JavaTXCompiler;
 import de.dhbwstuttgart.exceptions.DebugException;
-import de.dhbwstuttgart.syntaxtree.factory.UnifyTypeFactory;
-import de.dhbwstuttgart.syntaxtree.type.ExtendsWildcardType;
-import de.dhbwstuttgart.syntaxtree.type.RefType;
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 import de.dhbwstuttgart.typeinference.unify.interfaces.IRuleSet;
 import de.dhbwstuttgart.typeinference.unify.model.*;
 import de.dhbwstuttgart.typeinference.constraints.Constraint;
-import de.dhbwstuttgart.typeinference.unify.distributeVariance;
 
-import java.io.FileWriter;
 import java.io.IOException;
 import java.io.Writer;
 import java.io.OutputStreamWriter;
 
-import org.apache.commons.io.output.NullOutputStream;
-
 /**
  * Implementation of the type inference rules.
  * @author Florian Steurer
@@ -37,17 +31,17 @@ import org.apache.commons.io.output.NullOutputStream;
  */
 public class RuleSet implements IRuleSet{
 	
-	Writer logFile;
+	Logger logger;
 	final PlaceholderRegistry placeholderRegistry;
 	
 	public RuleSet(PlaceholderRegistry placeholderRegistry) {
 		super();
-		logFile = OutputStreamWriter.nullWriter();
+		logger = Logger.NULL_LOGGER;
 		this.placeholderRegistry = placeholderRegistry;
 	}
 	
-	RuleSet(Writer logFile, PlaceholderRegistry placeholderRegistry) {
-		this.logFile = logFile;
+	RuleSet(Logger logger, PlaceholderRegistry placeholderRegistry) {
+		this.logger = logger;
 		this.placeholderRegistry = placeholderRegistry;
 	}
 	
@@ -300,8 +294,8 @@ public class RuleSet implements IRuleSet{
 		
 		if(dFromFc == null || !dFromFc.getTypeParams().arePlaceholders() || dFromFc.getTypeParams().size() != cFromFc.getTypeParams().size())
 			return Optional.empty();
-		//System.out.println("cFromFc: " + cFromFc);
-		//System.out.println("dFromFc: " + dFromFc);
+		//context.logger().info("cFromFc: " + cFromFc);
+		//context.logger().info("dFromFc: " + dFromFc);
 		int[] pi = pi(cFromFc.getTypeParams(), dFromFc.getTypeParams());
 		
 		if(pi.length == 0)
@@ -510,17 +504,17 @@ public class RuleSet implements IRuleSet{
 		TypeParams typeDParams = typeD.getTypeParams();
 		TypeParams typeDgenParams = typeDgen.getTypeParams();
 		
-		//System.out.println("Pair: " +pair);
-		//System.out.println("typeD: " +typeD);
-		//System.out.println("typeDParams: " +typeDParams);
-		//System.out.println("typeDgen: " +typeD);
-		//System.out.println("typeDgenParams: " +typeDgenParams);
+		//context.logger().info("Pair: " +pair);
+		//context.logger().info("typeD: " +typeD);
+		//context.logger().info("typeDParams: " +typeDParams);
+		//context.logger().info("typeDgen: " +typeD);
+		//context.logger().info("typeDgenParams: " +typeDgenParams);
 		Unifier unif = Unifier.identity();
 		for(int i = 0; i < typeDParams.size(); i++) { 
-			//System.out.println("ADAPT" +typeDgenParams);
+			//context.logger().info("ADAPT" +typeDgenParams);
 			if (typeDgenParams.get(i) instanceof PlaceholderType) 
-			unif.add((PlaceholderType) typeDgenParams.get(i), typeDParams.get(i));
-			else System.out.println("ERROR");
+				unif.add((PlaceholderType) typeDgenParams.get(i), typeDParams.get(i));
+			else logger.exception(new Exception("ERROR in adapt rule: cannot add non placeholder type"));
 		}
 		return Optional.of(new UnifyPair(unif.apply(newLhs), typeDs, PairOperator.SMALLERDOT, pair.getSubstitution(), pair.getBasePair()));
 	}
@@ -655,9 +649,11 @@ public class RuleSet implements IRuleSet{
 	
 	@Override
 	public Optional<Set<UnifyPair>> subst(Set<UnifyPair> pairs, List<Set<Constraint<UnifyPair>>> oderConstraints) {
-		HashMap<UnifyType, Integer> typeMap = new HashMap<>();
+		// Statistically, typeMap will fill up quickly and resize multiple times. To reduce this, we start with a higher capacity
+		HashMap<UnifyType, Integer> typeMap = new HashMap<>(200);
 		
 		Stack<UnifyType> occuringTypes = new Stack<>();
+		occuringTypes.ensureCapacity(pairs.size() * 3);
 
 		for(UnifyPair pair : pairs) {
 			occuringTypes.push(pair.getLhsType());
@@ -675,9 +671,9 @@ public class RuleSet implements IRuleSet{
 			if(t1 instanceof SuperType)
 				occuringTypes.push(((SuperType) t1).getSuperedType());
 			else
-				t1.getTypeParams().forEach(x -> occuringTypes.push(x));	
+				t1.getTypeParams().forEach(occuringTypes::push);
 		}
-		Queue<UnifyPair> result1 = new LinkedList<UnifyPair>(pairs);
+		LinkedList<UnifyPair> result1 = new LinkedList<UnifyPair>(pairs);
 		ArrayList<UnifyPair> result = new ArrayList<UnifyPair>();
 		boolean applied = false;
 
@@ -698,19 +694,30 @@ public class RuleSet implements IRuleSet{
 					&& !((rhsType instanceof WildcardType) && ((WildcardType)rhsType).getWildcardedType().equals(lhsType))) //PL eigefuegt 2018-02-18
 			{
 				Unifier uni = new Unifier(lhsType,  rhsType);
-				result = result.stream().map(x -> uni.apply(pair,x)).collect(Collectors.toCollection(ArrayList::new));
-				result1 = result1.stream().map(x -> uni.apply(pair,x)).collect(Collectors.toCollection(LinkedList::new));
+				// apply unifier to result and result1 in place
+				result.replaceAll(p -> uni.apply(pair, p));
+				ListIterator<UnifyPair> result1Iterator = result1.listIterator();
+				while (result1Iterator.hasNext()) {
+					UnifyPair x = result1Iterator.next();
+					result1Iterator.set(uni.apply(pair, x));
+				}
 
 				Function<? super Constraint<UnifyPair>,? extends Constraint<UnifyPair>> applyUni = b -> b.stream().map(
 						x -> uni.apply(pair,x)).collect(Collectors.toCollection((b.getExtendConstraint() != null)
 								? () -> new Constraint<UnifyPair>(
 										  b.isInherited(),
 										  b.isImplemented(),
-										  b.getExtendConstraint().stream().map(x -> uni.apply(pair,x)).collect(Collectors.toCollection(Constraint::new)),
+										  b.getExtendConstraint().createdMapped(x -> uni.apply(pair,x)),
 										  b.getmethodSignatureConstraint().stream().map(x -> uni.apply(pair,x)).collect(Collectors.toCollection(HashSet::new)))
 								: () -> new Constraint<UnifyPair>(b.isInherited(), b.isImplemented())
 									));
-				oderConstraints.replaceAll(oc -> oc.stream().map(applyUni).collect(Collectors.toCollection(HashSet::new)));
+				oderConstraints.replaceAll(oc -> {
+						HashSet<Constraint<UnifyPair>> mapped = new HashSet<>(oc.size());
+						for (var element : oc) {
+							mapped.add(applyUni.apply(element));
+						}
+						return mapped;
+				});
 				/*
 						oderConstraints = oderConstraints.stream().map(
 						a -> a.stream().map(applyUni
@@ -864,14 +871,11 @@ public class RuleSet implements IRuleSet{
         								   UnifyType r = x.getRhsType();
         								   if (r instanceof PlaceholderType) { ((PlaceholderType)r).disableWildcardtable(); }
 								     } );
-		try {
-			logFile.write("FUNgreater: " + pair + "\n");
-				logFile.write("FUNred: " + result + "\n");
-				// logFile.flush();
-			}
-		catch (IOException e) {
-			System.out.println("logFile-Error");
-		}
+
+		logger.debug(() -> "FUNgreater: " + pair);
+		logger.debug(() -> "FUNred: " + result);
+
+
 		return Optional.of(result);
 	}
 	
@@ -937,8 +941,8 @@ public class RuleSet implements IRuleSet{
 
 		Set<UnifyPair> result = new HashSet<UnifyPair>();
 		
-		Integer variance = ((PlaceholderType)rhsType).getVariance();
-		Integer inversVariance = distributeVariance.inverseVariance(variance);
+		int variance = ((PlaceholderType)rhsType).getVariance();
+		int inversVariance = distributeVariance.inverseVariance(variance);
 		
 		UnifyType[] freshPlaceholders = new UnifyType[funNLhsType.getTypeParams().size()];
 		for(int i = 0; i < freshPlaceholders.length-1; i++) {
@@ -960,14 +964,10 @@ public class RuleSet implements IRuleSet{
 									   UnifyType r = x.getRhsType();
 									   if (r instanceof PlaceholderType) { ((PlaceholderType)r).disableWildcardtable(); }
 									 } );
-		try {
-			logFile.write("FUNgreater: " + pair + "\n");
-			logFile.write("FUNgreater: " + result + "\n");
-			// logFile.flush();
-		}
-	catch (IOException e) {
-		System.out.println("lofFile-Error");
-	}
+
+		logger.debug(() -> "FUNgreater: " + pair);
+		logger.debug(() -> "FUNgreater: " + result);
+
 		return Optional.of(result);
 	}
 
@@ -986,8 +986,8 @@ public class RuleSet implements IRuleSet{
 
 		Set<UnifyPair> result = new HashSet<UnifyPair>();
 		
-		Integer variance = ((PlaceholderType)lhsType).getVariance();
-		Integer inversVariance = distributeVariance.inverseVariance(variance);
+		int variance = ((PlaceholderType)lhsType).getVariance();
+		int inversVariance = distributeVariance.inverseVariance(variance);
 		
 		UnifyType[] freshPlaceholders = new UnifyType[funNRhsType.getTypeParams().size()];
 		for(int i = 0; i < freshPlaceholders.length-1; i++) {
@@ -1010,14 +1010,11 @@ public class RuleSet implements IRuleSet{
 		   							   UnifyType r = x.getRhsType();
 		   							   if (r instanceof PlaceholderType) { ((PlaceholderType)r).disableWildcardtable(); }
 									 } );
-		try {
-			logFile.write("FUNgreater: " + pair + "\n");
-			logFile.write("FUNsmaller: " + result + "\n");
-			// logFile.flush();
-		}
-	catch (IOException e) {
-		System.out.println("lofFile-Error");
-	}
+
+
+		logger.debug(() -> "FUNgreater: " + pair);
+		logger.debug(() -> "FUNsmaller: " + result);
+
 		return Optional.of(result);
 	}
 

src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnify.java

@@ -29,17 +29,12 @@ public class TypeUnify {
 	 * unify parallel ohne result modell
 	 */
 	public static Set<Set<UnifyPair>> unify(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, UnifyContext unifyContext) {
-		ForkJoinPool pool = TypeUnify.createThreadPool();
+		ForkJoinPool pool = TypeUnify.createThreadPool(unifyContext.logger());
 		UnifyContext context = unifyContext.newWithParallel(true).newWithExecutor(pool);
 		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, context, 0);
 		Set<Set<UnifyPair>> res = joinFuture(unifyTask.compute());
-		try {
-			unifyContext.logFile().write("\nnoShortendElements: " + TypeUnifyTask.noShortendElements + "\n");
-			// logFile.flush();
-		}
-		catch (IOException e) {
-			System.err.println("no log-File");
-		}
+
+		unifyContext.logger().debug("\nnoShortendElements: " + TypeUnifyTask.noShortendElements + "\n");
 		return res;
 	}
 	
@@ -47,7 +42,7 @@ public class TypeUnify {
 	 * unify asynchron mit Rückgabe UnifyResultModel ohne dass alle results gesammelt sind
 	 */
 	public static UnifyResultModel unifyAsync(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, UnifyContext unifyContext) {
-		ForkJoinPool pool = TypeUnify.createThreadPool();
+		ForkJoinPool pool = TypeUnify.createThreadPool(unifyContext.logger());
 		UnifyContext context = unifyContext.newWithExecutor(pool);
 		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, context, 0);
 		unifyTask.compute();
@@ -58,18 +53,12 @@ public class TypeUnify {
 	 * unify parallel mit Rückgabe UnifyResultModel nachdem alle results gesammelt sind
 	 */
 	public static Set<Set<UnifyPair>> unifyParallel(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, UnifyContext unifyContext) {
-		ForkJoinPool pool = TypeUnify.createThreadPool();
+		ForkJoinPool pool = TypeUnify.createThreadPool(unifyContext.logger());
 		UnifyContext context = unifyContext.newWithParallel(true).newWithExecutor(pool);
 		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, context, 0);
 		var result = joinFuture(unifyTask.compute());
 
-		try {
-			unifyContext.logFile().write("\nnoShortendElements: " + TypeUnifyTask.noShortendElements +"\n");
-			// logFile.flush();
-		}
-		catch (IOException e) {
-			System.err.println("no log-File");
-		}
+		unifyContext.logger().debug("\nnoShortendElements: " + TypeUnifyTask.noShortendElements + "\n");
 		return result;
 	}
 	
@@ -87,18 +76,12 @@ public class TypeUnify {
 	public static Set<Set<UnifyPair>> unifyOderConstraints(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, UnifyContext unifyContext) {
 		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, unifyContext.newWithParallel(false), 0);
 		Set<Set<UnifyPair>> res = joinFuture(unifyTask.compute());
-		try {
-			unifyContext.logFile().write("\nnoShortendElements: " + TypeUnifyTask.noShortendElements +"\n");
-			// logFile.flush();
-		}
-		catch (IOException e) {
-			System.err.println("no log-File");
-		}
+		unifyContext.logger().debug("\nnoShortendElements: " + TypeUnifyTask.noShortendElements +"\n");
 		return res;
 	}
 
-	private static ForkJoinPool createThreadPool() {
-		Logger.print("Available processors: " + Runtime.getRuntime().availableProcessors());
+	private static ForkJoinPool createThreadPool(Logger logger) {
+		logger.info("Available processors: " + Runtime.getRuntime().availableProcessors());
 		return new ForkJoinPool(
 			Runtime.getRuntime().availableProcessors(),
 			ForkJoinPool.defaultForkJoinWorkerThreadFactory,

src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnify2Task.java

@@ -34,7 +34,7 @@ public class TypeUnify2Task extends TypeUnifyTask {
   @Override
   public CompletableFuture<Set<Set<UnifyPair>>> compute() {
     if (one) {
-      System.out.println("two");
+      context.logger().info("two");
     }
     one = true;
     CompletableFuture<Set<Set<UnifyPair>>> res =
@@ -53,12 +53,6 @@ public class TypeUnify2Task extends TypeUnifyTask {
   }
 
   public void closeLogFile() {
-
-    try {
-      context.logFile().close();
-    } catch (IOException ioE) {
-      System.err.println("no log-File");
-    }
-
+    context.logger().close();
   }
 }

src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java

@@ -3,6 +3,7 @@ package de.dhbwstuttgart.typeinference.unify;
 
 import de.dhbwstuttgart.exceptions.TypeinferenceException;
 import de.dhbwstuttgart.parser.NullToken;
+import de.dhbwstuttgart.server.ServerTaskLogger;
 import de.dhbwstuttgart.typeinference.constraints.Constraint;
 import de.dhbwstuttgart.typeinference.unify.cartesianproduct.VarianceCase;
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
@@ -45,8 +46,8 @@ import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Future;
 import java.util.concurrent.RecursiveTask;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BiFunction;
 import java.util.function.BinaryOperator;
@@ -66,7 +67,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
   private static int i = 0;
   private final boolean printtag = false;
 
-  final UnifyContext context;
+  public final UnifyContext context;
 
   /**
    * Element, das aus dem nextSet den Gleichunen dieses Threads hinzugefuegt wurde
@@ -108,21 +109,21 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 
   int rekTiefeField;
 
-  Integer nOfUnify = 0;
+  int nOfUnify = 0;
 
-  Integer noUndefPair = 0;
+  int noUndefPair = 0;
 
-  Integer noAllErasedElements = 0;
+  int noAllErasedElements = 0;
 
   // some statistics for local output (they will not make sense when executed on the server)
   public static int noBacktracking;
   public static int noShortendElements;
   public static int noou = 0;
 
-  Boolean myIsCanceled = false;
+  boolean myIsCanceled = false;
 
   public TypeUnifyTask(UnifyContext context) {
-    this.context = context.newWithLogFile(new OutputStreamWriter(NullOutputStream.INSTANCE));
+    this.context = context.newWithLogger(Logger.NULL_LOGGER);
     rules = new RuleSet(context.placeholderRegistry());
   }
 
@@ -157,24 +158,19 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     this.fc = fc;
     this.oup = new OrderingUnifyPair(fc, context);
 
-    Writer logFileWriter = OutputStreamWriter.nullWriter();
-    if (context.log()) {
-      try {
-        logFileWriter = new FileWriter(System.getProperty("user.dir") + "/logFiles/" + "Thread");
-        logFileWriter.write("");
-      } catch (IOException e) {
-        System.err.println("log-File nicht vorhanden");
-      }
-    }
-    this.context = context.newWithLogFile(logFileWriter);
-
+    this.context = (context.logger() instanceof ServerTaskLogger) ? context : context.newWithLogger(
+      Logger.forFile(
+        System.getProperty("user.dir") + "/logFiles/" + "Thread",
+        "Unify"
+      )
+    );
 
     /*Abbruchtest
     if (thNo > 10) {
-      System.out.println("cancel");
+      context.logger().info("cancel");
       usedTasks.cancel();
       writeLog(nOfUnify.toString() + "cancel");
-      System.out.println("cancel");
+      context.logger().info("cancel");
       try {
         logFile.write("Abbruch");
       }
@@ -183,7 +179,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
       }
     }
     */
-    rules = new RuleSet(context.logFile(), context.placeholderRegistry());
+    rules = new RuleSet(context.logger(), context.placeholderRegistry());
     this.rekTiefeField = rekTiefe;
     context.usedTasks().add(this);
   }
@@ -220,7 +216,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 		}		
 }
 */
-  void myCancel(Boolean b) {
+  void myCancel(boolean b) {
     myIsCanceled = true;
   }
 
@@ -230,7 +226,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 
   public CompletableFuture<Set<Set<UnifyPair>>> compute() {
     if (one) {
-      System.out.println("two");
+      context.logger().info("two");
     }
     one = true;
     Set<UnifyPair> neweq = new HashSet<>(eq);
@@ -247,11 +243,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
       .collect(Collectors.toCollection(ArrayList::new));
     var unifyFuture = unify(neweq, remainingOderconstraints, fc, context.parallel(), rekTiefeField, methodSignatureConstraint);
     return unifyFuture.thenApply(res -> {
-      try {
-        context.logFile().close();
-      } catch (IOException ioE) {
-        System.err.println("no log-File");
-      }
+      context.logger().close();
       if (isUndefinedPairSetSet(res)) {
         //fuer debug-Zwecke
         ArrayList<ArrayList<UnifyPair>> al = res.stream()
@@ -292,7 +284,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     //		).collect(Collectors.toCollection(HashSet::new));
     //writeLog(nOfUnify.toString() + " AA: " + aas.toString());
     //if (aas.isEmpty()) {
-    //	System.out.println("");
+    //	context.logger().info("");
     //}
 
     //.collect(Collectors.toCollection(HashSet::new)));
@@ -303,8 +295,8 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 
     rekTiefe++;
     nOfUnify++;
-    writeLog(nOfUnify.toString() + " Unifikation: " + eq.toString());
-    writeLog(nOfUnify.toString() + " Oderconstraints: " + oderConstraints.toString());
+    context.logger().debug(() -> nOfUnify + " Unifikation: " + eq.toString());
+    context.logger().debug(() -> nOfUnify + " Oderconstraints: " + oderConstraints.toString());
 
     /*
      * Variancen auf alle Gleichungen vererben
@@ -326,15 +318,10 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     /*
      * Occurs-Check durchfuehren
      */
-    Set<UnifyPair> ocurrPairs = eq.stream().filter(x -> {
-        UnifyType lhs, rhs;
-        return (lhs = x.getLhsType()) instanceof PlaceholderType
-          && !((rhs = x.getRhsType()) instanceof PlaceholderType)
-          && rhs.getTypeParams().occurs((PlaceholderType) lhs);
-      })
-      .peek(UnifyPair::setUndefinedPair)
-      .collect(Collectors.toCollection(HashSet::new));
-    writeLog("ocurrPairs: " + ocurrPairs);
+    Set<UnifyPair> ocurrPairs = TypeUnifyTaskHelper.occursCheck(eq);
+
+    Set<UnifyPair> finalOcurrPairs = ocurrPairs;
+    context.logger().debug(() -> "ocurrPairs: " + finalOcurrPairs);
     if (!ocurrPairs.isEmpty()) {
       Set<Set<UnifyPair>> ret = new HashSet<>();
       ret.add(ocurrPairs);
@@ -355,15 +342,9 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
       /* In commit dfd91b5f8b7fca1cb5f302eec4b0ba3330271c9b eingefuegt ANFANG */
       Set<UnifyPair> occurcheck = new HashSet<>(eq0);
       occurcheck.removeAll(eq0Prime);
-      ocurrPairs = occurcheck.stream().filter(x -> {
-          UnifyType lhs, rhs;
-          return (lhs = x.getLhsType()) instanceof PlaceholderType
-            && !((rhs = x.getRhsType()) instanceof PlaceholderType)
-            && rhs.getTypeParams().occurs((PlaceholderType) lhs);
-        })
-        .peek(UnifyPair::setUndefinedPair)
-        .collect(Collectors.toCollection(HashSet::new));
-      writeLog("ocurrPairs: " + ocurrPairs);
+      ocurrPairs = TypeUnifyTaskHelper.occursCheck(occurcheck);
+      Set<UnifyPair> finalOcurrPairs1 = ocurrPairs;
+      context.logger().debug(() -> "ocurrPairs: " + finalOcurrPairs1);
       if (!ocurrPairs.isEmpty()) {
         Set<Set<UnifyPair>> ret = new HashSet<>();
         ret.add(ocurrPairs);
@@ -375,8 +356,8 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 
     eq0.forEach(UnifyPair::disableCondWildcards);
 
-    writeLog(nOfUnify.toString() + " Unifikation nach applyTypeUnificationRules: " + eq.toString());
-    writeLog(nOfUnify.toString() + " Oderconstraints nach applyTypeUnificationRules: " + oderConstraints.toString());
+    context.logger().debug(() ->nOfUnify + " Unifikation nach applyTypeUnificationRules: " + eq.toString());
+    context.logger().debug(() -> nOfUnify + " Oderconstraints nach applyTypeUnificationRules: " + oderConstraints.toString());
 
     /*
      * Step 2 and 3: Create a subset eq1s of pairs where both sides are TPH and eq2s of the other pairs
@@ -396,7 +377,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     // cartesian product of the sets created by pattern matching.
     List<Set<? extends Set<UnifyPair>>> topLevelSets = new ArrayList<>();
 
-    //System.out.println(eq2s);
+    //context.logger().info(eq2s);
 
     if (!eq1s.isEmpty()) { // Do not add empty sets or the cartesian product will always be empty.
       Set<Set<UnifyPair>> wrap = new HashSet<>();
@@ -420,7 +401,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     // Sets that originate from pair pattern matching
     // Sets of the "second level"
     Set<UnifyPair> undefinedPairs = new HashSet<>();
-    if (printtag) System.out.println("eq2s " + eq2s);
+    if (printtag) context.logger().info("eq2s " + eq2s);
     //writeLog("BufferSet: " + bufferSet.toString()+"\n");
     List<Set<Constraint<UnifyPair>>> oderConstraintsOutput = new ArrayList<>();//new ArrayList<>(oderConstraints);
     Set<Set<Set<? extends Set<UnifyPair>>>> secondLevelSets = calculatePairSets(eq2s, oderConstraints, fc, undefinedPairs, oderConstraintsOutput);
@@ -428,21 +409,21 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     //nicht ausgewertet Faculty Beispiel im 1. Schritt
     //PL 2017-10-03 geloest, muesste noch mit FCs mit kleineren
     //Typen getestet werden.
-    writeLog(nOfUnify.toString() + " Oderconstraints2: " + oderConstraintsOutput.toString());
-    if (printtag) System.out.println("secondLevelSets:" + secondLevelSets);
+    context.logger().debug(() -> nOfUnify + " Oderconstraints2: " + oderConstraintsOutput.toString());
+    if (printtag) context.logger().info("secondLevelSets:" + secondLevelSets);
     // If pairs occured that did not match one of the cartesian product cases,
     // those pairs are contradictory and the unification is impossible.
     if (!undefinedPairs.isEmpty()) {
       noUndefPair++;
       for (UnifyPair up : undefinedPairs) {
-        writeLog(noUndefPair.toString() + " UndefinedPairs; " + up);
-        writeLog("BasePair; " + up.getBasePair());
+        context.logger().debug(() -> noUndefPair + " UndefinedPairs; " + up);
+        context.logger().debug(() -> "BasePair; " + up.getBasePair());
       }
       Set<Set<UnifyPair>> error = new HashSet<>();
       undefinedPairs = undefinedPairs.stream().peek(UnifyPair::setUndefinedPair)
         .collect(Collectors.toCollection(HashSet::new));
       error.add(undefinedPairs);
-      undefinedPairs.forEach(x -> writeLog("AllSubst: " + x.getAllSubstitutions().toString()));
+      undefinedPairs.forEach(x -> context.logger().debug(() -> "AllSubst: " + x.getAllSubstitutions().toString()));
       return CompletableFuture.completedFuture(error);
     }
 
@@ -452,16 +433,16 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     // Alternative: Sub cartesian products of the second level (pattern matched) sets
     // "the big (x)"
 		/* for(Set<Set<Set<UnifyPair>>> secondLevelSet : secondLevelSets) {
-			//System.out.println("secondLevelSet "+secondLevelSet.size());
+			//context.logger().info("secondLevelSet "+secondLevelSet.size());
 			List<Set<Set<UnifyPair>>> secondLevelSetList = new ArrayList<>(secondLevelSet);
 			Set<List<Set<UnifyPair>>> cartResult = setOps.cartesianProduct(secondLevelSetList);
-			//System.out.println("CardResult: "+cartResult.size());
+			//context.logger().info("CardResult: "+cartResult.size());
 			// Flatten and add to top level sets
 			Set<Set<UnifyPair>> flat = new HashSet<>();
 			int j = 0;
 			for(List<Set<UnifyPair>> s : cartResult) {
 				j++;
-				//System.out.println("s from CardResult: "+cartResult.size() + " " + j);
+				//context.logger().info("s from CardResult: "+cartResult.size() + " " + j);
 				Set<UnifyPair> flat1 = new HashSet<>();
 				for(Set<UnifyPair> s1 : s)
 					flat1.addAll(s1);
@@ -475,8 +456,8 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     for (Set<Set<? extends Set<UnifyPair>>> secondLevelSet : secondLevelSets) {
       topLevelSets.addAll(secondLevelSet);
     }
-    //System.out.println(topLevelSets);
-    //System.out.println();
+    //context.logger().info(topLevelSets);
+    //context.logger().info();
 
 
     //Aufruf von computeCartesianRecursive ANFANG
@@ -517,18 +498,18 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
      * Step 5: Substitution
      */
     //writeLog("vor Subst: " + eqPrime);
-    writeLog("vor Subst: " + oderConstraints);
+    context.logger().debug(() -> "vor Subst: " + oderConstraints);
     String ocString = oderConstraints.toString();
     List<Set<Constraint<UnifyPair>>> newOderConstraints = new ArrayList<>(oderConstraints);
     Optional<Set<UnifyPair>> eqPrimePrime = rules.subst(eqPrime, newOderConstraints);
     Set<Set<UnifyPair>> unifyres1 = null;
     Set<Set<UnifyPair>> unifyres2 = null;
     if (!ocString.equals(newOderConstraints.toString()))
-      writeLog("nach Subst: " + newOderConstraints);
+      context.logger().debug(() -> "nach Subst: " + newOderConstraints);
 
 
     {// sequentiell (Step 6b is included)
-      if (printtag) System.out.println("nextStep: " + eqPrimePrime);
+      if (printtag) context.logger().info("nextStep: " + eqPrimePrime);
       if (eqPrime.equals(eq) && eqPrimePrime.isEmpty()
         && oderConstraints.isEmpty()) {                    //PL 2017-09-29 //(!eqPrimePrime.isPresent()) auskommentiert und durch
         //PL 2017-09-29 dies ersetzt //(!eqPrimePrime.isPresent())
@@ -547,12 +528,12 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
           return eqPrimePrimeSet;
         });
         if (finalresult && isSolvedForm(eqPrime)) {
-          writeLog("eqPrime:" + eqPrime.toString() + "\n");
+          context.logger().debug(() -> "eqPrime:" + eqPrime.toString() + "\n");
 
           /* methodconstraintsets werden zum Ergebnis hinzugefuegt
            * Anfang
            */
-          //System.out.println("methodSignatureConstraint Return: " + methodSignatureConstraint + "\n");
+          //context.logger().info("methodSignatureConstraint Return: " + methodSignatureConstraint + "\n");
           eqPrimePrimeSetFuture = eqPrimePrimeSetFuture.thenApply(eqPrimePrimeSet -> {
             eqPrimePrimeSet.forEach(x -> x.addAll(methodSignatureConstraint));
 
@@ -603,7 +584,8 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     return eqPrimePrimeSetFuture.thenApply(eqPrimePrimeSet -> {
       eqPrimePrimeSet = eqPrimePrimeSet.stream().filter(x -> isSolvedForm(x) || this.isUndefinedPairSet(x)).collect(Collectors.toCollection(HashSet::new));
       if (!eqPrimePrimeSet.isEmpty() && !isUndefinedPairSetSet(eqPrimePrimeSet)) {
-        writeLog("Result1 " + eqPrimePrimeSet);
+        Set<Set<UnifyPair>> finalEqPrimePrimeSet = eqPrimePrimeSet;
+        context.logger().debug(() -> "Result1 " + finalEqPrimePrimeSet);
       }
       return eqPrimePrimeSet;
     });
@@ -675,7 +657,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     } else {
       //Varianz-Bestimmung Oder-Constraints
       if (printtag) {
-        System.out.println("nextSetasList " + nextSetAsList);
+        context.logger().info("nextSetasList " + nextSetAsList);
       }
       variance = TypeUnifyTaskHelper.calculateOderConstraintVariance(nextSetAsList);
     }
@@ -691,14 +673,16 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
      */
     Set<UnifyPair> sameEqSet = new HashSet<>();
     //optOrigPair enthaelt ggf. das Paar a = ty \in  nextSet
-    Optional<UnifyPair> optOrigPair = Optional.empty();
+    Optional<UnifyPair> optOrigPair;
     if (!oderConstraint) {
       optOrigPair = TypeUnifyTaskHelper.findEqualityConstrainedUnifyPair(nextSetElement);
-      writeLog("optOrigPair: " + optOrigPair);
+      context.logger().debug(() -> "optOrigPair: " + optOrigPair);
 
       if (optOrigPair.isPresent()) {
         sameEqSet = TypeUnifyTaskHelper.findConstraintsWithSameTVAssociation(optOrigPair.get(), singleElementSets);
       }
+    } else {
+      optOrigPair = Optional.empty();
     }
 
 
@@ -708,7 +692,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 
     return resultFuture.thenApply(result -> {
       //2020-02-02: if (variance ==2) Hier Aufruf von filterOverriding einfuegen
-      writeLog("Return computeCR: " + result.toString());
+      context.logger().debug(() ->"Return computeCR: " + result.toString());
       return result;
     });
   }
@@ -735,23 +719,23 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 
     VarianceCase varianceCase = VarianceCase.createFromVariance(variance, oderConstraint, this, context);
 
-    writeLog("nextSet: " + nextSet.toString());
-    writeLog("nextSetasList: " + prevNextSetAsList.toString());
+    context.logger().debug(() -> "nextSet: " + nextSet.toString());
+    context.logger().debug(() -> "nextSetasList: " + prevNextSetAsList.toString());
 
     varianceCase.selectNextData(this, prevNextSetAsList, optOrigPair);
 
     if (oderConstraint) {//Methodconstraints werden abgespeichert für die Bytecodegenerierung von Methodenaufrufen
       methodSignatureConstraint.addAll(((Constraint<UnifyPair>) varianceCase.a).getmethodSignatureConstraint());
-      writeLog("ERSTELLUNG methodSignatureConstraint: " + methodSignatureConstraint);
-      //System.out.println("ERSTELLUNG methodSignatureConstraint: " +noOfThread+" "+methodSignatureConstraint);
-      //System.out.println("a: " +a);
-      //System.out.println("eq: " +eq);
-      //System.out.println();
+      context.logger().debug(() -> "ERSTELLUNG methodSignatureConstraint: " + methodSignatureConstraint);
+      //context.logger().info("ERSTELLUNG methodSignatureConstraint: " +noOfThread+" "+methodSignatureConstraint);
+      //context.logger().info("a: " +a);
+      //context.logger().info("eq: " +eq);
+      //context.logger().info();
     }
 
     i++;
     Set<Set<UnifyPair>> elems = new HashSet<>(singleElementSets);
-    writeLog("a1: " + rekTiefe + "  " + "variance:  " + variance + " " + varianceCase.a.toString() + "\n");
+    context.logger().debug(() -> "a1: " + rekTiefe + "  " + "variance:  " + variance + " " + varianceCase.a.toString() + "\n");
 
     Set<Set<UnifyPair>> aParDef = new HashSet<>();
 
@@ -774,6 +758,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     // - fork results : forkResults (frueher "add_res")
     CompletableFuture<Tuple<Set<Set<UnifyPair>>, Set<Set<Set<UnifyPair>>>>> parallelResultDataFuture;
 
+
     if (parallel) {
       parallelResultDataFuture = varianceCase.computeParallel(
         elems, eq, oderConstraints, fc, rekTiefe, methodSignatureConstraint,
@@ -798,7 +783,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
       //Ab hier alle parallele Berechnungen wieder zusammengeführt.
       if (oderConstraint) {//Wenn weiteres Element nextSetasList genommen wird, muss die vorherige methodsignatur geloescht werden
         methodSignatureConstraint.removeAll(((Constraint<UnifyPair>) varianceCase.a).getmethodSignatureConstraint());
-        //System.out.println("REMOVE: " +methodSignatureConstraint);
+        //context.logger().info("REMOVE: " +methodSignatureConstraint);
       }
       if (!isUndefinedPairSetSet(currentThreadResult) && isUndefinedPairSetSet(result)) {
         //wenn korrektes Ergebnis gefunden alle Fehlerfaelle loeschen
@@ -816,16 +801,16 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 
             //Alle Variablen bestimmen die nicht hinzugefügt wurden in a
             //PL 2018-12-28: Hier gab es eine ClassCastException, war nicht reproduzierbar
-            // System.out.println("");
+            // context.logger().info("");
             List<PlaceholderType> vars_a = TypeUnifyTaskHelper.extractMatchingPlaceholderTypes(varianceCase.a);
             Set<UnifyPair> fstElemRes = currentThreadResult.iterator().next();
             Set<UnifyPair> compRes = fstElemRes.stream().filter(x -> vars_a.contains(((PlaceholderType) x.getLhsType()))).collect(Collectors.toCollection(HashSet::new));
 
             //Alle Variablen bestimmen die nicht hinzugefügt wurden in a_last
-            //System.out.println(a_last);
+            //context.logger().info(a_last);
 
             try {//PL eingefuegt 2019-03-06 da bei map mmer wieder Nullpointer kamen
-              a_last.forEach(x -> writeLog("a_last_elem:" + x + " basepair: " + x.getBasePair()));//PL 2019-05-13 ins try hinzugefuegt Nullpointer-Exception ist in der Zeile aufgetaucht.
+              a_last.forEach(x -> context.logger().debug(() -> "a_last_elem:" + x + " basepair: " + x.getBasePair()));//PL 2019-05-13 ins try hinzugefuegt Nullpointer-Exception ist in der Zeile aufgetaucht.
               List<PlaceholderType> varsLast_a = TypeUnifyTaskHelper.extractMatchingPlaceholderTypes(a_last);
               //[(java.util.Vector<java.lang.Integer> <. gen_aq, , 1), (CEK =. ? extends gen_aq, 1)] KANN VORKOMMEN
               //erstes Element genügt, da vars immer auf die gleichen Elemente zugeordnet werden muessen
@@ -834,11 +819,12 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 
               varianceCase.applyComputedResults(result, currentThreadResult, compResult, compRes);
             } catch (NullPointerException e) {
-              writeLog("NullPointerException: " + a_last.toString());
+              context.logger().debug(() -> "NullPointerException: " + a_last.toString());
             }
           } else {
             //alle Fehlerfaelle und alle korrekten Ergebnis jeweils adden
-            writeLog("RES Fst: result: " + result.toString() + " currentThreadResult: " + currentThreadResult.toString());
+            Set<Set<UnifyPair>> finalResult = result;
+            context.logger().debug(() -> "RES Fst: result: " + finalResult.toString() + " currentThreadResult: " + currentThreadResult.toString());
             result.addAll(currentThreadResult);
           }
         }
@@ -856,14 +842,15 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
             //wenn korrektes Ergebnis gefunden alle Fehlerfaelle loeschen
             result = par_res;
             if (!par_res.isEmpty() && par_res.iterator().next() instanceof WildcardType) {
-              // System.out.println();
+              // context.logger().info();
             }
           } else {
             if ((isUndefinedPairSetSet(par_res) && isUndefinedPairSetSet(result))
               || (!isUndefinedPairSetSet(par_res) && !isUndefinedPairSetSet(result))
               || result.isEmpty()) {
               //alle Fehlerfaelle und alle korrekten Ergebnis jeweils adden
-              writeLog("RES var1 ADD:" + result.toString() + " " + par_res.toString());
+              Set<Set<UnifyPair>> finalResult1 = result;
+              context.logger().debug(() ->"RES var1 ADD:" + finalResult1.toString() + " " + par_res.toString());
               result.addAll(par_res);
             }
           }
@@ -887,12 +874,11 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
           return CompletableFuture.completedFuture(result);
         }
 
-        writeLog("a: " + rekTiefe + " variance: " + variance + varianceCase.a.toString());
+        context.logger().debug(() -> "a: " + rekTiefe + " variance: " + variance + varianceCase.a.toString());
       }
       /* auskommentiert um alle Max und min Betrachtung auszuschalten ENDE */
 
       if (isUndefinedPairSetSet(currentThreadResult) && aParDef.isEmpty()) {
-        int nofstred = 0;
         Set<UnifyPair> abhSubst = TypeUnifyTaskHelper.collectFromThreadResult(currentThreadResult, UnifyPair::getAllSubstitutions);
         abhSubst.addAll(
           TypeUnifyTaskHelper.collectFromThreadResult(currentThreadResult, UnifyPair::getThisAndAllBases)
@@ -922,9 +908,10 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
         */
 
         if (currentThreadResult.size() > 1) {
-          // System.out.println();
+          // context.logger().info();
         }
-        writeLog("nextSetasList vor filter-Aufruf: " + nextSetAsList);
+        List<Set<UnifyPair>> finalNextSetAsList = nextSetAsList;
+        context.logger().debug(() -> "nextSetasList vor filter-Aufruf: " + finalNextSetAsList);
         if (!oderConstraint) {//PL 2023-02-08 eingefuegt: Bei oderconstraints sind Subststitutionen nicht als Substitutionen in idesem Sinne zu sehen
           nextSetAsList = nextSetAsList.stream().filter(x -> {
               //Boolean ret = false;
@@ -935,24 +922,29 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
             })//.filter(y -> couldBecorrect(reducedUndefResSubstGroundedBasePair, y)) //fuer testzwecke auskommentiert um nofstred zu bestimmen PL 2018-10-10
             .collect(Collectors.toCollection(ArrayList::new));
         }
-        writeLog("nextSetasList nach filter-Aufruf: " + nextSetAsList);
-        nofstred = nextSetAsList.size();
-        //NOCH NICHT korrekt PL 2018-10-12
-        //nextSetasList = nextSetasList.stream().filter(y -> couldBecorrect(reducedUndefResSubstGroundedBasePair, y))
-        //			.collect(Collectors.toCollection(ArrayList::new));
-        writeLog("currentThreadResult (undef): " + currentThreadResult.toString());
-        writeLog("abhSubst: " + abhSubst.toString());
-        writeLog("a2: " + rekTiefe + " " + varianceCase.a.toString());
-        writeLog("Durchschnitt: " + durchschnitt.toString());
-        writeLog("nextSet: " + nextSet.toString());
-        writeLog("nextSetasList: " + nextSetAsList.toString());
-        writeLog("Number first erased Elements (undef): " + (len - nofstred));
-        writeLog("Number second erased Elements (undef): " + (nofstred - nextSetAsList.size()));
-        writeLog("Number erased Elements (undef): " + (len - nextSetAsList.size()));
-        noAllErasedElements += (len - nextSetAsList.size());
-        writeLog("Number of all erased Elements (undef): " + noAllErasedElements.toString());
-        writeLog("Number of Backtracking: " + noBacktracking++);
-        // System.out.println("");
+
+        if (context.logger().isLogLevelActive(Logger.LogLevel.DEBUG)) {
+          List<Set<UnifyPair>> finalNextSetAsList1 = nextSetAsList;
+          context.logger().debug(() -> "nextSetasList nach filter-Aufruf: " + finalNextSetAsList1);
+          int nofstred = nextSetAsList.size();
+          //NOCH NICHT korrekt PL 2018-10-12
+          //nextSetasList = nextSetasList.stream().filter(y -> couldBecorrect(reducedUndefResSubstGroundedBasePair, y))
+          //			.collect(Collectors.toCollection(ArrayList::new));
+          context.logger().debug("currentThreadResult (undef): " + currentThreadResult.toString());
+          context.logger().debug("abhSubst: " + abhSubst.toString());
+          context.logger().debug("a2: " + rekTiefe + " " + varianceCase.a.toString());
+          context.logger().debug("Durchschnitt: " + durchschnitt.toString());
+          context.logger().debug("nextSet: " + nextSet.toString());
+          context.logger().debug("nextSetasList: " + nextSetAsList.toString());
+          context.logger().debug("Number first erased Elements (undef): " + (len - nofstred));
+          context.logger().debug("Number second erased Elements (undef): " + (nofstred - nextSetAsList.size()));
+          context.logger().debug("Number erased Elements (undef): " + (len - nextSetAsList.size()));
+          noAllErasedElements += (len - nextSetAsList.size());
+          context.logger().debug("Number of all erased Elements (undef): " + noAllErasedElements);
+          context.logger().debug("Number of Backtracking: " + noBacktracking++);
+        }
+
+        // context.logger().info("");
       }
       //if (nextSetasList.size() == 0 && isUndefinedPairSetSet(result) && nextSet.size() > 1) {
       //	return result;
@@ -961,7 +953,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
       //	result.removeIf(y -> isUndefinedPairSet(y));
       //}
       //else result.stream().filter(y -> !isUndefinedPairSet(y));
-      writeLog("currentThreadResult: " + currentThreadResult.toString());
+      context.logger().debug(() -> "currentThreadResult: " + currentThreadResult.toString());
 
       return this.innerCartesianLoop(variance, rekTiefe, oderConstraint, parallel, result, varianceCase.a, nextSet,
         nextSetAsList, optOrigPair, methodSignatureConstraint, singleElementSets, sameEqSet, oderConstraints);
@@ -978,7 +970,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
    *                  the error constraints. Error constraints are added
    * @result contradiction of (a = ty) in sameEqSet
    */
-  public Boolean checkNoContradiction(Set<UnifyPair> a, Set<UnifyPair> sameEqSet, Set<Set<UnifyPair>> result) {
+  public boolean checkNoContradiction(Set<UnifyPair> a, Set<UnifyPair> sameEqSet, Set<Set<UnifyPair>> result) {
 
     //optAPair enthaelt ggf. das Paar a = ty' \in a
     //unterscheidet sich von optOrigPair, da dort a = ty
@@ -998,7 +990,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
       UnifyPair aPair = optAPair.get();
       //writeLog("optOrigPair: " + optOrigPair + " " + "aPair: " + aPair+ " " + "aPair.basePair(): " + aPair.getBasePair());
 
-      writeLog("checkA: " + aPair + "sameEqSet: " + sameEqSet);
+      context.logger().debug(() ->"checkA: " + aPair + "sameEqSet: " + sameEqSet);
       for (UnifyPair sameEq : sameEqSet) {
         if (sameEq.getLhsType() instanceof PlaceholderType) {
           Set<UnifyPair> localEq = new HashSet<>();
@@ -1019,7 +1011,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
             if (result.isEmpty() || isUndefinedPairSetSet(result)) {
               result.addAll(localRes);
             }
-            writeLog("FALSE: " + aPair + "sameEqSet: " + sameEqSet);
+            context.logger().debug(() ->"FALSE: " + aPair + "sameEqSet: " + sameEqSet);
             return false;
           }
         } else {
@@ -1041,12 +1033,12 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
             if (result.isEmpty() || isUndefinedPairSetSet(result)) {
               result.addAll(localRes);
             }
-            writeLog("FALSE: " + aPair + "sameEqSet: " + sameEqSet);
+            context.logger().debug(() ->"FALSE: " + aPair + "sameEqSet: " + sameEqSet);
             return false;
           }
         }
       }
-      writeLog("TRUE: " + aPair + "sameEqSet: " + sameEqSet);
+      context.logger().debug(() ->"TRUE: " + aPair + "sameEqSet: " + sameEqSet);
       return true;
     }
     return true;
@@ -1132,7 +1124,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
             // Through application of the rules, every pair should have one of the above forms.
             // Pairs that do not have one of the aboves form are contradictory.
             else {
-              writeLog("Second erase:" + checkPair);
+              context.logger().debug(() ->"Second erase:" + checkPair);
               return false;
             }
             //*/
@@ -1331,7 +1323,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
    * (as in case 1 where sigma is added to the innermost set).
    */
   protected Set<Set<Set<? extends Set<UnifyPair>>>> calculatePairSets(Set<UnifyPair> eq2s, List<Set<Constraint<UnifyPair>>> oderConstraintsInput, IFiniteClosure fc, Set<UnifyPair> undefined, List<Set<Constraint<UnifyPair>>> oderConstraintsOutput) {
-    writeLog("eq2s: " + eq2s.toString());
+    context.logger().debug(() ->"eq2s: " + eq2s.toString());
     oderConstraintsOutput.addAll(oderConstraintsInput);
     List<Set<Set<? extends Set<UnifyPair>>>> result = new ArrayList<>(9);
 
@@ -1384,15 +1376,13 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     {
       List<Set<Constraint<UnifyPair>>> oderConstraintsVariance = oderConstraintsOutput.stream() //Alle Elemente rauswerfen, die Variance 0 haben oder keine TPH in LHS oder RHS sind
         .filter(x -> x.stream()
-          .anyMatch(y ->
-            y.stream().anyMatch(z ->
-              ( (z.getLhsType() instanceof PlaceholderType)
-                && (((PlaceholderType) (z.getLhsType())).getVariance() != 0))
-              ||
-              ( (z.getRhsType() instanceof PlaceholderType)
-                && (((PlaceholderType) (z.getRhsType())).getVariance() != 0))
-            )
-          )).toList();
+          .filter(y ->
+            y.stream().filter(z -> ((z.getLhsType() instanceof PlaceholderType)
+              && (((PlaceholderType) (z.getLhsType())).getVariance() != 0))
+              || ((z.getRhsType() instanceof PlaceholderType)
+              && (((PlaceholderType) (z.getRhsType())).getVariance() != 0))
+            ).findFirst().isPresent()
+          ).findFirst().isPresent()).collect(Collectors.toList());
       if (!oderConstraintsVariance.isEmpty()) {
         Set<Constraint<UnifyPair>> ret = oderConstraintsVariance.getFirst();
         oderConstraintsOutput.remove(ret);
@@ -1420,10 +1410,12 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
       }
     }
 
-    writeLog("eq2s: " + eq2s);
-    writeLog("eq2sAsListFst: " + eq2sAsListFst);
-    writeLog("eq2sAsListSnd: " + eq2sAsListSnd);
-    writeLog("eq2sAsListBack: " + eq2sAsListBack);
+    if (context.logger().isLogLevelActive(Logger.LogLevel.DEBUG)) {
+      context.logger().debug("eq2s: " + eq2s);
+      context.logger().debug("eq2sAsListFst: " + eq2sAsListFst);
+      context.logger().debug("eq2sAsListSnd: " + eq2sAsListSnd);
+      context.logger().debug("eq2sAsListBack: " + eq2sAsListBack);
+    }
 
     eq2sAsList.addAll(eq2sAsListFst);
     eq2sAsList.addAll(eq2sAsListSnd);
@@ -1436,7 +1428,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
       if (!oderConstraintsOutput.isEmpty()) {
         Set<Constraint<UnifyPair>> ret = oderConstraintsOutput.removeFirst();
         //if (ret.iterator().next().iterator().next().getLhsType().getName().equals("M"))
-        //	System.out.println("M");
+        //	context.logger().info("M");
         //Set<UnifyPair> retFlat = new HashSet<>();
         //ret.stream().forEach(x -> retFlat.addAll(x));
 
@@ -1476,7 +1468,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
 
       // Case 1: (a <. Theta')
       if (((pairOp == PairOperator.SMALLERDOT) || (pairOp == PairOperator.SMALLERNEQDOT)) && lhsType instanceof PlaceholderType) {
-        //System.out.println(pair);
+        //context.logger().info(pair);
         if (first) { //writeLog(pair.toString()+"\n");
           Set<Set<UnifyPair>> x1 = new HashSet<>();
           if (pair.getRhsType().getName().equals("void")) {
@@ -1498,7 +1490,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
             x1.remove(remElem);
           }
 					/* ZU LOESCHEN ANFANG
-				//System.out.println(x1);
+				//context.logger().info(x1);
 					Set<UnifyPair> sameEqSet = eq2sAsList.stream()
 							  .filter(x -> ((x.getLhsType().equals(lhsType) || x.getRhsType().equals(lhsType)) && !x.equals(pair)))
 							  .collect(Collectors.toCollection(HashSet::new));
@@ -1716,11 +1708,11 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     //		&& ((ReferenceType)thetaPrime).getTypeParams().iterator().next() instanceof PlaceholderType) //.getName().equals("java.util.Vector"))
     //		&& ((ReferenceType)((ReferenceType)thetaPrime).getTypeParams().iterator().next()).getTypeParams().iterator().next().getName().equals("java.lang.Integer")) {
     //		{
-    //		System.out.println("");
+    //		context.logger().info("");
     //}
     Set<UnifyType> cs = fc.getAllTypesByName(thetaPrime.getName());//cs= [java.util.Vector<NP>, java.util.Vector<java.util.Vector<java.lang.Integer>>, ????java.util.Vector<gen_hv>???]
 
-    writeLog("cs: " + cs.toString());
+    context.logger().debug(() ->"cs: " + cs.toString());
     //PL 18-02-06 entfernt, kommt durch unify wieder rein
     //cs.add(thetaPrime);
     //PL 18-02-06 entfernt
@@ -1731,8 +1723,9 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
         aa.putAll(b);
         return aa;
       };
-      HashMap<PlaceholderType, PlaceholderType> hm = x.getInvolvedPlaceholderTypes().stream()
-        .reduce(new HashMap<PlaceholderType, PlaceholderType>(),
+      var involvedPlaceholderTypes = x.getInvolvedPlaceholderTypes();
+      HashMap<PlaceholderType, PlaceholderType> hm = involvedPlaceholderTypes.stream()
+        .reduce(TypeUnifyTaskHelper.getPresizedHashMap(involvedPlaceholderTypes.size()),
           (aa, b) -> {
             aa.put(b, PlaceholderType.freshPlaceholder(context.placeholderRegistry()));
             return aa;
@@ -1752,7 +1745,8 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
       if ((match.match(ml)).isEmpty()) {
         thetaQs.remove(c);
       }
-      writeLog("thetaQs von " + c + ": " + thetaQs.toString());
+      Set<UnifyType> finalThetaQs = thetaQs;
+      context.logger().debug(() ->"thetaQs von " + c + ": " + finalThetaQs.toString());
       //Set<UnifyType> thetaQs = fc.getChildren(c).stream().collect(Collectors.toCollection(HashSet::new));
       //thetaQs.add(thetaPrime); //PL 18-02-05 wieder geloescht
       //PL 2017-10-03: War auskommentiert habe ich wieder einkommentiert,
@@ -1776,7 +1770,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
         for (TypeParams tp : permuteParams(candidateParams))
           thetaQPrimes.add(c.setTypeParams(tp));
       }
-      writeLog("thetaQPrimes von " + c + ": " + thetaQPrimes.toString());
+      context.logger().debug(() ->"thetaQPrimes von " + c + ": " + thetaQPrimes.toString());
       for (UnifyType tqp : thetaQPrimes) {//PL 2020-03-08 umbauen in der Schleife wird nur unifizierbarer Typ gesucht break am Ende
         Collection<PlaceholderType> tphs = tqp.getInvolvedPlaceholderTypes();
         Optional<Unifier> opt = stdUnify.unify(tqp, thetaPrime);
@@ -1803,7 +1797,13 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
           //eingefuegt PL 2018-03-29 Anfang ? ext. theta hinzufuegen
           if (a.isWildcardable()) {
             Set<UnifyType> smaller_ext = smaller.stream().filter(x -> !(x instanceof ExtendsType) && !(x instanceof SuperType))
-              .map(ExtendsType::new)//.accept(new freshPlaceholder(), hm));}
+              .map(x -> {
+                //BinaryOperator<HashMap<PlaceholderType,PlaceholderType>> combiner = (aa,b) -> { aa.putAll(b); return aa;}; //Variablenumbenennung rausgenommen
+                //HashMap<PlaceholderType,PlaceholderType> hm = x.getInvolvedPlaceholderTypes().stream()                   //Variablen muessen wahrscheinlich erhalten bleiben
+                //		.reduce(new HashMap<PlaceholderType,PlaceholderType>(),
+                //				(aa, b)-> { aa.put(b,PlaceholderType.freshPlaceholder()); return aa; }, combiner);
+                return new ExtendsType(x);
+              })//.accept(new freshPlaceholder(), hm));}
               .collect(Collectors.toCollection(HashSet::new));
             smaller.addAll(smaller_ext);
           }
@@ -1843,7 +1843,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
         }
       }
     }
-    writeLog("result von " + pair + ": " + result);
+    context.logger().debug(() ->"result von " + pair + ": " + result);
     return result;
   }
 
@@ -1923,7 +1923,13 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
     //writeLog("GREATER: " + greater + pair + "THETA: " + theta + "FBOUNDED: " + pair.getfBounded() + " ");
     if (a.isWildcardable()) {
       Set<UnifyType> greater_ext = greater.stream().filter(x -> !(x instanceof ExtendsType) && !(x instanceof SuperType))
-        .map(SuperType::new)//.accept(new freshPlaceholder(), hm));}
+        .map(x -> {
+          //BinaryOperator<HashMap<PlaceholderType,PlaceholderType>> combiner = (aa,b) -> { aa.putAll(b); return aa;}; //Variablenumbenennung rausgenommen
+          //HashMap<PlaceholderType,PlaceholderType> hm = x.getInvolvedPlaceholderTypes().stream()                   //Variablen muessen wahrscheinlich erhalten bleiben
+          //		.reduce(new HashMap<PlaceholderType,PlaceholderType>(),
+          //				(aa, b)-> { aa.put(b,PlaceholderType.freshPlaceholder()); return aa; }, combiner);
+          return new SuperType(x);
+        })//.accept(new freshPlaceholder(), hm));}
         .collect(Collectors.toCollection(HashSet::new));
       greater.addAll(greater_ext);
     }
@@ -1948,7 +1954,7 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
           return ((match.match(termList).isPresent()) || x);
         };
         //if (parai.getName().equals("java.lang.Integer")) {
-        //	System.out.println("");
+        //	context.logger().info("");
         //}
         BinaryOperator<Boolean> bo = (x, y) -> (x || y);
         if (fBounded.stream().reduce(false, f, bo)) {
@@ -2038,22 +2044,4 @@ public class TypeUnifyTask extends RecursiveTask<CompletableFuture<Set<Set<Unify
       permuteParams(candidates, idx + 1, result, current);
     }
   }
-
-  public void writeLog(String str) {
-    if (context.log() && finalresult) {
-      synchronized (context.logFile()) {
-        try {
-					/*
-					logFile.write("Thread no.:" + thNo + "\n");
-					logFile.write("noOfThread:" + noOfThread + "\n");
-					logFile.write("parallel:" + parallel + "\n");
-					 */
-          context.logFile().write(str + "\n\n");
-          // logFile.flush();
-        } catch (IOException e) {
-          System.err.println("kein LogFile");
-        }
-      }
-    }
-  }
 }

src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTaskHelper.java

@@ -5,6 +5,7 @@ import de.dhbwstuttgart.typeinference.unify.model.PlaceholderType;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyType;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Optional;
@@ -185,4 +186,36 @@ public class TypeUnifyTaskHelper {
       .collect(Collectors.toCollection(ArrayList::new));
   }
 
+
+  public static Set<UnifyPair> occursCheck(final Set<UnifyPair> eq) {
+    Set<UnifyPair> ocurrPairs = new HashSet<>(eq.size());
+    for (UnifyPair x : eq) {
+      UnifyType lhs = x.getLhsType();
+      UnifyType rhs = x.getRhsType();
+      if (lhs instanceof PlaceholderType lhsPlaceholder &&
+        !(rhs instanceof PlaceholderType) &&
+        rhs.getTypeParams().occurs(lhsPlaceholder))
+      {
+        x.setUndefinedPair();
+        ocurrPairs.add(x);
+      }
+    }
+    return ocurrPairs;
+  }
+
+
+  public static <T> HashSet<T> getPresizedHashSet(int minElements) {
+    if (minElements < 16) return new HashSet<>();
+    // HashSet and HashMap will resize at 75% load, so we account for that by multiplying with 1.5
+    int n = (int)(minElements * 1.5);
+    return new HashSet<>(n);
+  }
+
+  public static <S,T> HashMap<S,T> getPresizedHashMap(int minElements) {
+    if (minElements < 16) return new HashMap<>();
+    // HashSet and HashMap will resize at 75% load, so we account for that by multiplying with 1.5
+    int n = (int)(minElements * 1.5);
+    return new HashMap<>(n);
+  }
+
 }

src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyContext.java

@@ -1,17 +1,15 @@
 package de.dhbwstuttgart.typeinference.unify;
 
+import de.dhbwstuttgart.util.Logger;
 import java.io.Writer;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ForkJoinPool;
-import java.util.concurrent.atomic.AtomicInteger;
 
 public record UnifyContext(
-  // main log file of a unification
-  Writer logFile,
-  // if logs should be made
-  Boolean log,
+  // main logger of a unification
+  Logger logger,
   // if the unify algorithm should run in parallel
-  Boolean parallel,
+  boolean parallel,
   // the model for storing calculated results
   UnifyResultModel resultModel,
   // the executor used for thread management in parallel execution
@@ -23,26 +21,24 @@ public record UnifyContext(
 ) {
 
   public UnifyContext(
-    Writer logFile,
-    Boolean log,
-    Boolean parallel,
+    Logger logger,
+    boolean parallel,
     UnifyResultModel resultModel,
     UnifyTaskModel usedTasks,
     ExecutorService executor,
     PlaceholderRegistry placeholderRegistry
   ) {
-    this(logFile, log, parallel, resultModel, executor, placeholderRegistry, usedTasks);
+    this(logger, parallel, resultModel, executor, placeholderRegistry, usedTasks);
   }
 
   public UnifyContext(
-    Writer logFile,
-    Boolean log,
-    Boolean parallel,
+    Logger logger,
+    boolean parallel,
     UnifyResultModel resultModel,
     UnifyTaskModel usedTasks,
     PlaceholderRegistry placeholderRegistry
   ) {
-    this(logFile, log, parallel, resultModel, usedTasks, ForkJoinPool.commonPool(), placeholderRegistry);
+    this(logger, parallel, resultModel, usedTasks, ForkJoinPool.commonPool(), placeholderRegistry);
   }
 
 
@@ -51,20 +47,21 @@ public record UnifyContext(
    * causes the UnifyContext to be essentially handled as a
    */
 
-  public UnifyContext newWithLogFile(Writer logFile) {
-    return new UnifyContext(logFile, log, parallel, resultModel, executor, placeholderRegistry, usedTasks);
+  public UnifyContext newWithLogger(Logger logger) {
+    return new UnifyContext(logger, parallel, resultModel, executor, placeholderRegistry, usedTasks);
   }
 
   public UnifyContext newWithParallel(boolean parallel) {
-    return new UnifyContext(logFile, log, parallel, resultModel, executor, placeholderRegistry, usedTasks);
+    if (this.parallel == parallel) return this;
+    return new UnifyContext(logger, parallel, resultModel, executor, placeholderRegistry, usedTasks);
   }
 
   public UnifyContext newWithExecutor(ExecutorService executor) {
-    return new UnifyContext(logFile, log, parallel, resultModel, executor, placeholderRegistry, usedTasks);
+    return new UnifyContext(logger, parallel, resultModel, executor, placeholderRegistry, usedTasks);
   }
 
   public UnifyContext newWithResultModel(UnifyResultModel resultModel) {
-    return new UnifyContext(logFile, log, parallel, resultModel, executor, placeholderRegistry, usedTasks);
+    return new UnifyContext(logger, parallel, resultModel, executor, placeholderRegistry, usedTasks);
   }
 
 }

src/main/java/de/dhbwstuttgart/typeinference/unify/cartesianproduct/Variance0Case.java

@@ -75,7 +75,7 @@ public class Variance0Case extends VarianceCase {
     Set<UnifyPair> compResult,
     Set<UnifyPair> compRes
   ) {
-    writeLog("RES var=1 ADD:" + result.toString() + " " + currentThreadResult.toString());
+    context.logger().debug("RES var=1 ADD:" + result.toString() + " " + currentThreadResult.toString());
     result.addAll(currentThreadResult);
   }
 
@@ -90,7 +90,7 @@ public class Variance0Case extends VarianceCase {
     } else {
       nextSetAsList.removeAll(nextSetasListOderConstraints);
       nextSetasListOderConstraints = new ArrayList<>();
-      writeLog("Removed: " + nextSetasListOderConstraints);
+      context.logger().debug("Removed: " + nextSetasListOderConstraints);
       List<Set<UnifyPair>> smallerSetasList = typeUnifyTask.oup.smallerThan(a, nextSetAsList);
       List<Set<UnifyPair>> notInherited = smallerSetasList.stream()
         .filter(x -> !((Constraint<UnifyPair>) x).isInherited())
@@ -101,9 +101,9 @@ public class Variance0Case extends VarianceCase {
       erased.removeAll(notErased);
       nextSetAsList.removeAll(erased);
 
-      writeLog("Removed: " + erased);
+      context.logger().debug("Removed: " + erased);
 
-      writeLog("Not Removed: " + nextSetAsList);
+      context.logger().debug("Not Removed: " + nextSetAsList);
 
     }
     return false;

src/main/java/de/dhbwstuttgart/typeinference/unify/cartesianproduct/Variance1Case.java

@@ -32,12 +32,12 @@ public class Variance1Case extends VarianceCase {
     Optional<UnifyPair> optOrigPair
   ) {
     a = typeUnifyTask.oup.max(nextSetAsList.iterator());
-    writeLog("Max: a in " + variance + " " + a);
+    context.logger().debug("Max: a in " + variance + " " + a);
     nextSetAsList.remove(a);
     if (this.isOderConstraint) {
       nextSetasListOderConstraints.add(((Constraint<UnifyPair>) a).getExtendConstraint());
     }
-    writeLog("nextSetasListOderConstraints 1: " + nextSetasListOderConstraints);
+    context.logger().debug("nextSetasListOderConstraints 1: " + nextSetasListOderConstraints);
 
     //Alle maximale Elemente in nextSetasListRest bestimmen
     //nur für diese wird parallele Berechnung angestossen.
@@ -76,7 +76,7 @@ public class Variance1Case extends VarianceCase {
     CompletableFuture<Set<Set<UnifyPair>>> forkOrigFuture = CompletableFuture.supplyAsync(forkOrig::compute, context.executor()).thenCompose(f -> f);
     resultValues = resultValues.thenCombine(forkOrigFuture,
       (prevResults, currentThreadResult) -> {
-        forkOrig.writeLog("final Orig 1");
+        forkOrig.context.logger().debug("final Orig 1");
         forkOrig.closeLogFile();
         return new Tuple<>(currentThreadResult, prevResults.getSecond());
       });
@@ -87,12 +87,12 @@ public class Variance1Case extends VarianceCase {
     }
     /* FORK ENDE */
 
-    writeLog("a in " + variance + " " + a);
-    writeLog("nextSetasListRest: " + nextSetasListRest.toString());
+    context.logger().debug("a in " + variance + " " + a);
+    context.logger().debug("nextSetasListRest: " + nextSetasListRest.toString());
     while (!nextSetasListRest.isEmpty()) {
       Set<UnifyPair> nSaL = nextSetasListRest.removeFirst();
       nextSetAsList.remove(nSaL);
-      writeLog("1 RM" + nSaL.toString());
+      context.logger().debug("1 RM" + nSaL.toString());
 
       if (!this.isOderConstraint) {
         //ueberpruefung ob zu a =. ty \in nSaL in sameEqSet ein Widerspruch besteht
@@ -115,13 +115,13 @@ public class Variance1Case extends VarianceCase {
           if (typeUnifyTask.myIsCancelled()) {
             throw new UnifyCancelException();
           }
-          writeLog("fork_res: " + fork_res.toString());
-          writeLog(Boolean.valueOf((typeUnifyTask.isUndefinedPairSetSet(fork_res))).toString());
+          context.logger().debug("fork_res: " + fork_res.toString());
+          context.logger().debug(Boolean.valueOf((typeUnifyTask.isUndefinedPairSetSet(fork_res))).toString());
           prevResults.getSecond().add(fork_res);
           if (!typeUnifyTask.isUndefinedPairSetSet(fork_res)) {
             aParDef.add(fork.getNextSetElement());
           }
-          fork.writeLog("final 1");
+          fork.context.logger().debug("final 1");
           fork.closeLogFile();
         return prevResults;
         }
@@ -144,7 +144,7 @@ public class Variance1Case extends VarianceCase {
   ) {
     int resOfCompare = typeUnifyTask.oup.compare(compResult, compRes);
     if (resOfCompare == -1) {
-      writeLog("Geloescht result: " + result);
+      context.logger().debug("Geloescht result: " + result);
       result.clear();
       result.addAll(currentThreadResult);
     }
@@ -152,7 +152,7 @@ public class Variance1Case extends VarianceCase {
       result.addAll(currentThreadResult);
     }
     else if (resOfCompare == 1) {
-      writeLog("Geloescht currentThreadResult: " + currentThreadResult);
+      context.logger().debug("Geloescht currentThreadResult: " + currentThreadResult);
       //result = result;
     }
   }
@@ -163,35 +163,35 @@ public class Variance1Case extends VarianceCase {
     Set<Set<UnifyPair>> aParDef,
     List<Set<UnifyPair>> nextSetAsList
   ) {
-    // System.out.println("");
-    writeLog("a: " + rekTiefe + " variance: " + variance + a.toString());
-    writeLog("aParDef: " + aParDef.toString());
+    // context.logger().info("");
+    context.logger().debug("a: " + rekTiefe + " variance: " + variance + a.toString());
+    context.logger().debug("aParDef: " + aParDef.toString());
     aParDef.add(a);
     Iterator<Set<UnifyPair>> aParDefIt = aParDef.iterator();
     if (this.isOderConstraint) {
       nextSetAsList.removeAll(nextSetasListOderConstraints);
       nextSetasListOderConstraints = new ArrayList<>();
-      writeLog("Removed: " + nextSetasListOderConstraints);
+      context.logger().debug("Removed: " + nextSetasListOderConstraints);
       while (aParDefIt.hasNext()) {
         Set<UnifyPair> a_new = aParDefIt.next();
         List<Set<UnifyPair>> smallerSetasList = typeUnifyTask.oup.smallerThan(a_new, nextSetAsList);
-        writeLog("smallerSetasList: " + smallerSetasList);
+        context.logger().debug("smallerSetasList: " + smallerSetasList);
         List<Set<UnifyPair>> notInherited = smallerSetasList.stream()
           .filter(x -> !((Constraint<UnifyPair>) x).isInherited() && !((Constraint<UnifyPair>) x).isImplemented())
           .collect(Collectors.toCollection(ArrayList::new));
-        writeLog("notInherited: " + notInherited + "\n");
+        context.logger().debug("notInherited: " + notInherited + "\n");
         List<Set<UnifyPair>> notErased = new ArrayList<>();
         notInherited.forEach(x -> {
           notErased.addAll(typeUnifyTask.oup.smallerEqThan(x, smallerSetasList));
         });
         List<Set<UnifyPair>> erased = new ArrayList<>(smallerSetasList);
-        writeLog("notErased: " + notErased + "\n");
+        context.logger().debug("notErased: " + notErased + "\n");
         erased.removeAll(notErased);
         nextSetAsList.removeAll(erased);
 
-        writeLog("Removed: " + erased);
+        context.logger().debug("Removed: " + erased);
 
-        writeLog("Not Removed: " + nextSetAsList);
+        context.logger().debug("Not Removed: " + nextSetAsList);
 
       }
     } else {
@@ -201,9 +201,9 @@ public class Variance1Case extends VarianceCase {
         List<Set<UnifyPair>> erased = typeUnifyTask.oup.smallerEqThan(a_new, nextSetAsList);
         nextSetAsList.removeAll(erased);
 
-        writeLog("Removed: " + erased);
+        context.logger().debug("Removed: " + erased);
 
-        writeLog("Not Removed: " + nextSetAsList);
+        context.logger().debug("Not Removed: " + nextSetAsList);
       }
     }
 

src/main/java/de/dhbwstuttgart/typeinference/unify/cartesianproduct/Variance2Case.java

@@ -51,7 +51,7 @@ public class Variance2Case extends VarianceCase {
   ) {
     CompletableFuture<Tuple<Set<Set<UnifyPair>>, Set<Set<Set<UnifyPair>>>>> resultValuesFuture;
 
-    writeLog("var2einstieg");
+    context.logger().debug("var2einstieg");
     Set<TypeUnify2Task> forks = new HashSet<>();
     Set<UnifyPair> newEqOrig = new HashSet<>(eq);
     Set<Set<UnifyPair>> newElemsOrig = new HashSet<>(elems);
@@ -62,7 +62,7 @@ public class Variance2Case extends VarianceCase {
     TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, context, rekTiefe, new HashSet<>(methodSignatureConstraint));
     CompletableFuture<Set<Set<UnifyPair>>> forkOrigFuture = CompletableFuture.supplyAsync(forkOrig::compute, context.executor()).thenCompose(f -> f);
     resultValuesFuture = forkOrigFuture.thenApply((currentThreadResult) -> {
-      forkOrig.writeLog("final Orig 2");
+      forkOrig.context.logger().debug("final Orig 2");
       forkOrig.closeLogFile();
       return new Tuple<>(currentThreadResult, new HashSet<>());
     });
@@ -71,8 +71,8 @@ public class Variance2Case extends VarianceCase {
     }
     /* FORK ENDE */
 
-    writeLog("a in " + variance + " " + a);
-    writeLog("nextSetasListRest: " + nextSetasListRest.toString());
+    context.logger().debug(() -> "a in " + variance + " " + a);
+    context.logger().debug(() -> "nextSetasListRest: " + nextSetasListRest.toString());
 
     //Fuer parallele Berechnung der Oder-Contraints wird methodSignature kopiert
     //und jeweils die methodSignature von a bzw. nSaL wieder gelöscht, wenn es keine Lösung ist.
@@ -95,7 +95,7 @@ public class Variance2Case extends VarianceCase {
           throw new UnifyCancelException();
         }
         resultValues.getSecond().add(fork_res);
-        fork.writeLog("final 2");
+        fork.context.logger().debug("final 2");
         fork.closeLogFile();
         return resultValues;
       });

src/main/java/de/dhbwstuttgart/typeinference/unify/cartesianproduct/VarianceCase.java

@@ -104,9 +104,4 @@ public abstract class VarianceCase {
     Set<Set<UnifyPair>> aParDef,
     List<Set<UnifyPair>> nextSetAsList
   );
-
-  protected void writeLog(String s) {
-    typeUnifyTask.writeLog(s);
-  }
-
 }

src/main/java/de/dhbwstuttgart/typeinference/unify/cartesianproduct/VarianceM1Case.java

@@ -32,11 +32,11 @@ public class VarianceM1Case extends VarianceCase {
     Optional<UnifyPair> optOrigPair
   ) {
     a = typeUnifyTask.oup.min(nextSetAsList.iterator());
-    writeLog("Min: a in " + variance + " " + a);
+    context.logger().debug(() -> "Min: a in " + variance + " " + a);
     if (this.isOderConstraint) {
       nextSetasListOderConstraints.add(((Constraint<UnifyPair>) a).getExtendConstraint());
     }
-    writeLog("nextSetasListOderConstraints -1: " + nextSetasListOderConstraints);
+    context.logger().debug(() -> "nextSetasListOderConstraints -1: " + nextSetasListOderConstraints);
     nextSetAsList.remove(a);
 
     //Alle minimalen Elemente in nextSetasListRest bestimmen
@@ -76,7 +76,7 @@ public class VarianceM1Case extends VarianceCase {
     CompletableFuture<Set<Set<UnifyPair>>> forkOrigFuture = CompletableFuture.supplyAsync(forkOrig::compute, context.executor()).thenCompose(f -> f);
     resultValues = resultValues.thenCombine(forkOrigFuture,
       (prevResults, currentThreadResult) -> {
-        forkOrig.writeLog("final Orig -1");
+        forkOrig.context.logger().debug("final Orig -1");
         forkOrig.closeLogFile();
         return new Tuple<>(currentThreadResult, prevResults.getSecond());
       });
@@ -87,13 +87,13 @@ public class VarianceM1Case extends VarianceCase {
     }
     /* FORK ENDE */
 
-    writeLog("a in " + variance + " " + a);
-    writeLog("nextSetasListRest: " + nextSetasListRest.toString());
+    context.logger().debug(() -> "a in " + variance + " " + a);
+    context.logger().debug(() -> "nextSetasListRest: " + nextSetasListRest.toString());
 
     while (!nextSetasListRest.isEmpty()) {
       Set<UnifyPair> nSaL = nextSetasListRest.removeFirst();
       nextSetAsList.remove(nSaL);
-      writeLog("-1 RM" + nSaL.toString());
+      context.logger().debug(() -> "-1 RM" + nSaL.toString());
 
       if (!this.isOderConstraint) {
         //ueberpruefung ob zu a =. ty \in nSaL in sameEqSet ein Widerspruch besteht
@@ -116,13 +116,13 @@ public class VarianceM1Case extends VarianceCase {
           if (typeUnifyTask.myIsCancelled()) {
             throw new UnifyCancelException();
           }
-          writeLog("fork_res: " + fork_res.toString());
-          writeLog(Boolean.valueOf((typeUnifyTask.isUndefinedPairSetSet(fork_res))).toString());
+          context.logger().debug(() -> "fork_res: " + fork_res.toString());
+          context.logger().debug(() -> Boolean.valueOf((typeUnifyTask.isUndefinedPairSetSet(fork_res))).toString());
           prevResults.getSecond().add(fork_res);
           if (!typeUnifyTask.isUndefinedPairSetSet(fork_res)) {
             aParDef.add(fork.getNextSetElement());
           }
-          fork.writeLog("final -1");
+          fork.context.logger().debug("final -1");
           fork.closeLogFile();
         return prevResults;
         }
@@ -146,13 +146,13 @@ public class VarianceM1Case extends VarianceCase {
   ) {
     int resOfCompare = typeUnifyTask.oup.compare(compResult, compRes);
     if (resOfCompare == 1) {
-      writeLog("Geloescht result: " + result);
+      context.logger().debug(() -> "Geloescht result: " + result);
       result.clear();
       result.addAll(currentThreadResult);
     } else if (resOfCompare == 0) {
       result.addAll(currentThreadResult);
     } else if (resOfCompare == -1) {
-      writeLog("Geloescht currentThreadResult: " + currentThreadResult);
+      context.logger().debug(() -> "Geloescht currentThreadResult: " + currentThreadResult);
       //result = result;
     }
   }
@@ -164,14 +164,14 @@ public class VarianceM1Case extends VarianceCase {
     List<Set<UnifyPair>> nextSetAsList
   ) {
 
-    // System.out.println("");
-    writeLog("a: " + rekTiefe + " variance: " + variance + a.toString());
-    writeLog("aParDef: " + aParDef.toString());
+    // context.logger().info("");
+    context.logger().debug(() -> "a: " + rekTiefe + " variance: " + variance + a.toString());
+    context.logger().debug(() -> "aParDef: " + aParDef.toString());
     aParDef.add(a);
     Iterator<Set<UnifyPair>> aParDefIt = aParDef.iterator();
     if (this.isOderConstraint) {
       nextSetAsList.removeAll(nextSetasListOderConstraints);
-      writeLog("Removed: " + nextSetasListOderConstraints);
+      context.logger().debug(() -> "Removed: " + nextSetasListOderConstraints);
       nextSetasListOderConstraints = new ArrayList<>();
       while (aParDefIt.hasNext()) {
         Set<UnifyPair> a_new = aParDefIt.next();
@@ -204,9 +204,9 @@ public class VarianceM1Case extends VarianceCase {
         erased.removeAll(notErased);
         nextSetAsList.removeAll(erased);
 
-        writeLog("Removed: " + erased);
+        context.logger().debug(() -> "Removed: " + erased);
 
-        writeLog("Not Removed: " + nextSetAsList);
+        context.logger().debug(() -> "Not Removed: " + nextSetAsList);
 
       }
     } else {
@@ -217,9 +217,9 @@ public class VarianceM1Case extends VarianceCase {
 
         nextSetAsList.removeAll(erased);
 
-        writeLog("Removed: " + erased);
+        context.logger().debug(() -> "Removed: " + erased);
 
-        writeLog("Not Removed: " + nextSetAsList);
+        context.logger().debug(() -> "Not Removed: " + nextSetAsList);
       }
     }
 

src/main/java/de/dhbwstuttgart/typeinference/unify/distributeVariance.java

@@ -13,14 +13,11 @@ import de.dhbwstuttgart.typeinference.unify.model.UnifyType;
 public class distributeVariance extends visitUnifyTypeVisitor<Integer> {
 	
 	public static int inverseVariance(int variance) {
-		Integer ret = 0;
-		if (variance == 1) {
-		   ret = -1;
-		}
-		if (variance == -1) {
-			ret = 1;
-		}
-		return ret;
+		return switch (variance) {
+			case 1 -> -1;
+			case -1 -> 1;
+			default -> 0;
+		};
 	}
 
 
@@ -42,7 +39,7 @@ public class distributeVariance extends visitUnifyTypeVisitor<Integer> {
 		List<UnifyType> param = new ArrayList<>(funnty.getTypeParams().get().length);
 		param.addAll(Arrays.asList(funnty.getTypeParams().get()));
 		UnifyType resultType = param.remove(param.size()-1);
-		Integer htInverse = inverseVariance(ht);
+		int htInverse = inverseVariance(ht);
 		param = param.stream()
 				     .map(x -> x.accept(this, htInverse))
 				     .collect(Collectors.toCollection(ArrayList::new));

src/main/java/de/dhbwstuttgart/typeinference/unify/model/ExtendsType.java

@@ -24,9 +24,6 @@ public final class ExtendsType extends WildcardType implements ISerializableData
 	 */
 	public ExtendsType(UnifyType extendedType) {
 		super("? extends " + extendedType.getName(), extendedType);
-		if (extendedType instanceof ExtendsType) {
-			System.out.print("");
-		}
 	}
 
 	/**

src/main/java/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java

@@ -5,7 +5,9 @@ import de.dhbwstuttgart.server.packet.dataContainers.KeyStorage;
 import de.dhbwstuttgart.server.packet.dataContainers.serialized.SerialList;
 import de.dhbwstuttgart.server.packet.dataContainers.serialized.SerialMap;
 import de.dhbwstuttgart.typeinference.unify.PlaceholderRegistry;
+import de.dhbwstuttgart.typeinference.unify.TypeUnifyTaskHelper;
 import de.dhbwstuttgart.typeinference.unify.UnifyContext;
+import de.dhbwstuttgart.util.Logger;
 import java.io.IOException;
 import java.io.Writer;
 import java.util.ArrayList;
@@ -42,7 +44,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 	final JavaTXCompiler compiler;
 	final PlaceholderRegistry placeholderRegistry;
 
-	Writer logFile;
+	Logger logger;
 
 	/**
 	 * A map that maps every type to the node in the inheritance graph that contains that type.
@@ -73,10 +75,10 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 	/**
 	 * Creates a new instance using the inheritance tree defined in the pairs.
 	 */
-	public FiniteClosure(Set<UnifyPair> pairs, Writer logFile, JavaTXCompiler compiler, PlaceholderRegistry placeholderRegistry) {
+	public FiniteClosure(Set<UnifyPair> pairs, Logger logger, JavaTXCompiler compiler, PlaceholderRegistry placeholderRegistry) {
 		this.compiler = compiler;
 		this.placeholderRegistry = placeholderRegistry;
-		this.logFile = logFile;
+		this.logger = logger;
 		this.pairs = new HashSet<>(pairs);
 		inheritanceGraph = new HashMap<UnifyType, Node<UnifyType>>();
 		
@@ -125,7 +127,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 		}
 
 		// Build the alternative representation with strings as keys
-		strInheritanceGraph = new HashMap<>();
+		strInheritanceGraph = TypeUnifyTaskHelper.getPresizedHashMap(inheritanceGraph.size());
 		for(UnifyType key : inheritanceGraph.keySet()) {
 			if(!strInheritanceGraph.containsKey(key.getName()))
 				strInheritanceGraph.put(key.getName(), new HashSet<>());
@@ -134,8 +136,8 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 		}
 	}
 	
-	public FiniteClosure(Set<UnifyPair> constraints, Writer writer, PlaceholderRegistry placeholderRegistry) {
-		this(constraints, writer, null, placeholderRegistry);
+	public FiniteClosure(Set<UnifyPair> constraints, Logger logger, PlaceholderRegistry placeholderRegistry) {
+		this(constraints, logger, null, placeholderRegistry);
 	}
 
 	void testSmaller() {
@@ -159,7 +161,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 		
 		Set<UnifyType> ret;
 		if ((ret = smallerHash.get(new hashKeyType(type))) != null) {
-			//System.out.println(greaterHash);
+			//context.logger().info(greaterHash);
 			return new HashSet<>(ret);
 		}
 		
@@ -200,7 +202,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 				result.add(new Pair<>(t, fBounded));
 			}
 			catch (StackOverflowError e) {
-				// System.out.println("");
+				// context.logger().info("");
 			}
 			
 			// if C<...> <* C<...> then ... (third case in definition of <*)
@@ -238,8 +240,8 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 			}
 		}
 
-		HashSet<UnifyType> resut = result.stream().map(x -> x.getKey()).collect(Collectors.toCollection(HashSet::new));
-		if(resut.equals(types.stream().map(x -> x.getKey()).collect(Collectors.toCollection(HashSet::new))))
+		HashSet<UnifyType> resut = result.stream().map(Pair::getKey).collect(Collectors.toCollection(HashSet::new));
+		if(resut.equals(types.stream().map(Pair::getKey).collect(Collectors.toCollection(HashSet::new))))
 			return resut;
 		return computeSmaller(result);
 	}
@@ -271,9 +273,9 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 	@Override
 	//Eingefuegt PL 2018-05-24 F-Bounded Problematik
 	public Set<UnifyType> greater(UnifyType type, Set<UnifyType> fBounded, SourceLoc location) {
-		Set<UnifyType> ret;
-		if ((ret = greaterHash.get(new hashKeyType(type))) != null) {
-			//System.out.println(greaterHash);
+		Set<UnifyType> ret = greaterHash.get(new hashKeyType(type));
+		if (ret != null) {
+			//context.logger().info(greaterHash);
 			return new HashSet<>(ret);
 		}
 	
@@ -323,7 +325,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 			Set<UnifyType> fBoundedNew = new HashSet<>(fBounded);
 			fBoundedNew.add(theta1);
 			Set<UnifyType> theta2Set = candidate.getContentOfPredecessors();
-			//System.out.println("");
+			//context.logger().info("");
 			for(UnifyType theta2 : theta2Set) {
 				result.add(theta2.apply(sigma));
 				PairResultFBounded.add(new Pair<>(theta2.apply(sigma), fBoundedNew));
@@ -357,7 +359,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 					    return ((match.match(termList).isPresent()) || x);
 					};
 					//if (parai.getName().equals("java.lang.Integer")) {
-					//	System.out.println("");
+					//	context.logger().info("");
 					//}
 					BinaryOperator<Boolean> bo = (a,b) -> (a || b);
 					if (lfBounded.stream().reduce(false,f,bo)) {
@@ -370,7 +372,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 					}
 				}
 				permuteParams(paramCandidates).forEach(x -> result.add(t.setTypeParams(x)));
-				//System.out.println("");
+				//context.logger().info("");
 			}
 		}
 		
@@ -430,7 +432,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 					    return ((match.match(termList).isPresent()) || x);
 					};
 					if (parai.getName().equals("java.lang.Integer")) {
-						System.out.println("");
+						context.logger().info("");
 					}
 					BinaryOperator<Boolean> bo = (a,b) -> (a || b);
 					if (fBounded.stream().reduce(false,f,bo)) continue; //F-Bounded Endlosrekursion
@@ -469,7 +471,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 		}
 		
 		HashSet<UnifyType> resut = result.stream().map(x -> x.getKey()).collect(Collectors.toCollection(HashSet::new));
-		System.out.println(resut);
+		context.logger().info(resut);
 		if(resut.equals(types.stream().map(x -> x.getKey()).collect(Collectors.toCollection(HashSet::new))))
 			return resut;
 		return computeGreater(result);
@@ -505,35 +507,42 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 	public Set<UnifyType> grArg(ReferenceType type, Set<UnifyType> fBounded) {
 		Set<UnifyType> result = new HashSet<UnifyType>();
 		result.add(type);	
-        smaller(type, fBounded).forEach(x -> result.add(new SuperType(x)));
-        greater(type,fBounded).forEach(x -> result.add(new ExtendsType(x)));
+		smaller(type, fBounded).forEach(x -> result.add(new SuperType(x)));
+		greater(type,fBounded).forEach(x -> result.add(new ExtendsType(x)));
 		return result;
 	}
 	
 	@Override
 	public Set<UnifyType> grArg(FunNType type, Set<UnifyType> fBounded) {
-		Set<UnifyType> result = new HashSet<UnifyType>();
+		Set<UnifyType> smaller = smaller(type, fBounded);
+		Set<UnifyType> greater = greater(type, fBounded);
+
+		Set<UnifyType> result = new HashSet<UnifyType>((int)((1 + smaller.size() + greater.size()) * 1.5));
 		result.add(type);	
-        smaller(type, fBounded).forEach(x -> result.add(new SuperType(x)));
-        greater(type, fBounded).forEach(x -> result.add(new ExtendsType(x)));
+		smaller.forEach(x -> result.add(new SuperType(x)));
+		greater.forEach(x -> result.add(new ExtendsType(x)));
 		return result;
 	}
 	
 	@Override
 	public Set<UnifyType> grArg(ExtendsType type, Set<UnifyType> fBounded) {
-		Set<UnifyType> result = new HashSet<UnifyType>();
-		result.add(type);
 		UnifyType t = type.getExtendedType();
-		greater(t, fBounded).forEach(x -> result.add(new ExtendsType(x)));
+		Set<UnifyType> greater = greater(t, fBounded);
+
+		Set<UnifyType> result = new HashSet<UnifyType>((int)((1 + greater.size()) * 1.5));
+		result.add(type);
+		greater.forEach(x -> result.add(new ExtendsType(x)));
 		return result;
 	}
 
 	@Override
 	public Set<UnifyType> grArg(SuperType type, Set<UnifyType> fBounded) {
-		Set<UnifyType> result = new HashSet<UnifyType>();
-		result.add(type);
 		UnifyType t = type.getSuperedType();
-		smaller(t, fBounded).forEach(x -> result.add(new SuperType(x)));
+		Set<UnifyType> smaller = smaller(t, fBounded);
+
+		Set<UnifyType> result = TypeUnifyTaskHelper.getPresizedHashSet(1 + smaller.size());
+		result.add(type);
+		smaller.forEach(x -> result.add(new SuperType(x)));
 		return result;
 	}
 	
@@ -565,29 +574,33 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 	
 	@Override
 	public Set<UnifyType> smArg(ExtendsType type, Set<UnifyType> fBounded) {
-		Set<UnifyType> result = new HashSet<UnifyType>();
-		result.add(type);
 		UnifyType t = type.getExtendedType();
+		Set<UnifyType> smaller = smaller(t, fBounded);
+
+		Set<UnifyType> result = TypeUnifyTaskHelper.getPresizedHashSet(2 * (1 + smaller.size()));
+		result.add(type);
 		result.add(t);
-        smaller(t, fBounded).forEach(x -> { 
-        	result.add(new ExtendsType(x));
-        	result.add(x); 
-        });
+		smaller.forEach(x -> {
+			result.add(new ExtendsType(x));
+			result.add(x);
+		});
 		return result;
 	}
 	
 
 	@Override
 	public Set<UnifyType> smArg(SuperType type, Set<UnifyType> fBounded) {
-		Set<UnifyType> result = new HashSet<UnifyType>();
-		result.add(type);
 		UnifyType t = type.getSuperedType();
+		Set<UnifyType> greater = greater(t, fBounded);
+
+		Set<UnifyType> result = TypeUnifyTaskHelper.getPresizedHashSet(2 * (1 + greater.size()));
+		result.add(type);
 		result.add(t);
-//*** ACHTUNG das koennte FALSCH sein PL 2018-05-23 evtl. HashSet durch smArg durchschleifen	
-        greater(t, fBounded).forEach(x -> { 
-        	result.add(new SuperType(x));
-        	result.add(x); 
-        });
+		//*** ACHTUNG das koennte FALSCH sein PL 2018-05-23 evtl. HashSet durch smArg durchschleifen
+		greater.forEach(x -> {
+			result.add(new SuperType(x));
+			result.add(x);
+		});
 		return result;
 	}
 	
@@ -602,7 +615,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 	public Set<UnifyType> getAllTypesByName(String typeName) {
 		if(!strInheritanceGraph.containsKey(typeName))
 			return new HashSet<>();
-		return strInheritanceGraph.get(typeName).stream().map(x -> x.getContent()).collect(Collectors.toCollection(HashSet::new));
+		return strInheritanceGraph.get(typeName).stream().map(Node::getContent).collect(Collectors.toCollection(HashSet::new));
 	}
 
 	@Override
@@ -692,9 +705,9 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 	*/
 	
 	public int compare (UnifyType left, UnifyType right, PairOperator pairop, UnifyContext context) {
-		try {logFile.write("left: "+ left + " right: " + right + " pairop: " + pairop +"\n");} catch (IOException ie) {}
+		logger.debug(() -> "left: "+ left + " right: " + right + " pairop: " + pairop +"\n");
 		// if (left.getName().equals("Matrix") || right.getName().equals("Matrix"))
-		// 	System.out.println("");
+		// 	context.logger().info("");
 		/*
 		pairop = PairOperator.SMALLERDOTWC;
 		List<UnifyType> al = new ArrayList<>();
@@ -751,12 +764,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 		Set<UnifyPair> smallerRes = unifyTask.applyTypeUnificationRules(hs, this);
 		
 		//if (left.getName().equals("Vector") || right.getName().equals("AbstractList")) 
-		{try { 
-			logFile.write("\nsmallerRes: " + smallerRes);//"smallerHash: " + greaterHash.toString());
-			// logFile.flush();
-		}
-		catch (IOException e) {
-			System.err.println("no LogFile");}}
+		logger.debug(() -> "\nsmallerRes: " + smallerRes);//"smallerHash: " + greaterHash.toString());
 
 		//Gleichungen der Form a <./=. Theta oder Theta <./=. a oder a <./=. b sind ok.
 		Predicate<UnifyPair> delFun = x -> !((x.getLhsType() instanceof PlaceholderType || 
@@ -765,12 +773,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 													 ((WildcardType)x.getLhsType()).getWildcardedType().equals(x.getRhsType()))
 											 );
 		long smallerLen = smallerRes.stream().filter(delFun).count();
-		try { 
-			logFile.write("\nsmallerLen: " + smallerLen +"\n");
-			// logFile.flush();
-		}
-		catch (IOException e) {
-			System.err.println("no LogFile");}
+		logger.debug(() -> "\nsmallerLen: " + smallerLen +"\n");
 		if (smallerLen == 0) return -1;
 		else {
 			up = new UnifyPair(right, left, pairop);
@@ -780,12 +783,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 			Set<UnifyPair> greaterRes = unifyTask.applyTypeUnificationRules(hs, this);
 			
 			//if (left.getName().equals("Vector") || right.getName().equals("AbstractList")) 
-			{try { 
-				logFile.write("\ngreaterRes: " + greaterRes);//"smallerHash: " + greaterHash.toString());
-				// logFile.flush();
-			}
-			catch (IOException e) {
-				System.err.println("no LogFile");}}
+			logger.debug(() -> "\ngreaterRes: " + greaterRes);//"smallerHash: " + greaterHash.toString());
 
 			//Gleichungen der Form a <./=. Theta oder Theta <./=. a oder a <./=. b sind ok. 
 			long greaterLen = greaterRes.stream().filter(delFun).count();
@@ -807,7 +805,7 @@ public class FiniteClosure implements IFiniteClosure, ISerializableData {
 		var pairList = data.getList("pairs").assertListOfUUIDs();
 		Set<UnifyPair> pairs = pairList.stream()
 			.map(pairData -> UnifyPair.fromSerial(pairData, context, keyStorage)).collect(Collectors.toSet());
-		return new FiniteClosure(pairs, context.logFile(), context.placeholderRegistry());
+		return new FiniteClosure(pairs, context.logger(), context.placeholderRegistry());
 	}
 
 }

src/main/java/de/dhbwstuttgart/typeinference/unify/model/FunNType.java

@@ -81,7 +81,7 @@ public class FunNType extends UnifyType implements ISerializableData {
 	}
 
 	@Override
-	public Boolean wrongWildcard() {
+	public boolean wrongWildcard() {
 		return (new ArrayList<UnifyType>(Arrays.asList(getTypeParams()
 				.get())).stream().filter(x -> (x instanceof WildcardType)).findFirst().isPresent());
 	}

src/main/java/de/dhbwstuttgart/typeinference/unify/model/OrderingUnifyPair.java

@@ -48,12 +48,7 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 				return fc.compare(left.getRhsType(), right.getRhsType(), PairOperator.SMALLERDOT, context);
 		}}
 		catch (ClassCastException e) {
-			try {
-			((FiniteClosure)fc).logFile.write("ClassCastException: " + left.toString() + " " + left.getGroundBasePair() + "\n\n");
-			 // ((FiniteClosure)fc).logFile.flush();
-			}
-			catch (IOException ie) {
-			}
+			((FiniteClosure)fc).logger.debug(() -> "ClassCastException: " + left.toString() + " " + left.getGroundBasePair() + "\n\n");
 			return -99;
 		}
 	}
@@ -61,7 +56,7 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 	/*
 	public int compareEq (UnifyPair left, UnifyPair right) {
 		if (left == null || right == null)
-			System.out.println("Fehler");
+			context.logger().info("Fehler");
 		if (left.getLhsType() instanceof PlaceholderType) {
 			return fc.compare(left.getRhsType(), right.getRhsType(), left.getPairOp());
 		}
@@ -82,12 +77,12 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 						&& (((ExtendsType)right).getExtendedType().getName().equals("java.util.Vector"))
 						&& (((ReferenceType)((ExtendsType)right).getExtendedType()).getTypeParams().iterator().next() instanceof ExtendsType)))
 				{
-					// System.out.println("");
+					// context.logger().info("");
 				}
 				if (((right instanceof SuperType) && (((SuperType)right).getSuperedType().getName().equals("java.lang.Object")))
 		||((left instanceof SuperType) && (((SuperType)left).getSuperedType().getName().equals("java.lang.Object"))))
 {
-						// System.out.println("");
+						// context.logger().info("");
 					}
 		}
 			else	 {
@@ -109,11 +104,11 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 						&& (((ExtendsType)right).getExtendedType().getName().equals("java.util.Vector"))
 						&& (((ReferenceType)((ExtendsType)right).getExtendedType()).getTypeParams().iterator().next() instanceof ExtendsType)))
 				{
-					// System.out.println("");
+					// context.logger().info("");
 				}
 				if (right instanceof SuperType) 
 					{
-						// System.out.println("");
+						// context.logger().info("");
 					}
 			}
 				else	 {
@@ -176,83 +171,79 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 		left.add(p4);
 		*/
 
+		Set<UnifyPair> lefteq = new HashSet<>();
+		Set<UnifyPair> leftle = new HashSet<>();
+		Set<UnifyPair> leftlewc = new HashSet<>();
+		Set<UnifyPair> lefteqOder = new HashSet<>();
+		Set<UnifyPair> lefteqRet = new HashSet<>();
+		Set<UnifyPair> leftleOder = new HashSet<>();
+		for (var x : left) {
+			boolean isLeftPlaceholder = x.getLhsType() instanceof PlaceholderType;
+			boolean isRightPlaceholder = x.getRhsType() instanceof PlaceholderType;
+			boolean hasPlaceholder = isLeftPlaceholder || isRightPlaceholder;
 
-		Set<UnifyPair> lefteq = left.stream()
-				.filter(x -> (x.getLhsType() instanceof PlaceholderType && x.getPairOp() == PairOperator.EQUALSDOT))
-				.collect(Collectors.toCollection(HashSet::new));
-		Set<UnifyPair> righteq = right.stream()
-				.filter(x -> (x.getLhsType() instanceof PlaceholderType && x.getPairOp() == PairOperator.EQUALSDOT))
-				.collect(Collectors.toCollection(HashSet::new));
-		Set<UnifyPair> leftle = left.stream()
-				.filter(x -> ((x.getLhsType() instanceof PlaceholderType || x.getRhsType() instanceof PlaceholderType) 
-						      && x.getPairOp() == PairOperator.SMALLERDOT))
-				.collect(Collectors.toCollection(HashSet::new));
-		Set<UnifyPair> rightle = right.stream()
-				.filter(x -> ((x.getLhsType() instanceof PlaceholderType || x.getRhsType() instanceof PlaceholderType) 
-						      && x.getPairOp() == PairOperator.SMALLERDOT))
-				.collect(Collectors.toCollection(HashSet::new));
-		Set<UnifyPair> leftlewc = left.stream()
-				.filter(x -> ((x.getLhsType() instanceof PlaceholderType || x.getRhsType() instanceof PlaceholderType) 
-						      && x.getPairOp() == PairOperator.SMALLERDOTWC))
-				.collect(Collectors.toCollection(HashSet::new));
-		Set<UnifyPair> rightlewc = right.stream()
-				.filter(x -> ((x.getLhsType() instanceof PlaceholderType || x.getRhsType() instanceof PlaceholderType) 
-						      && x.getPairOp() == PairOperator.SMALLERDOTWC))
-				.collect(Collectors.toCollection(HashSet::new));
-		//System.out.println(left.toString());
+			if (isLeftPlaceholder && x.getPairOp() == PairOperator.EQUALSDOT) lefteq.add(x);
+			if (hasPlaceholder && x.getPairOp() == PairOperator.SMALLERDOT) leftle.add(x);
+			if (hasPlaceholder && x.getPairOp() == PairOperator.SMALLERDOTWC) leftlewc.add(x);
+
+			UnifyPair y = x.getGroundBasePair();
+			boolean isBasePairLeftPlaceholder = y.getLhsType() instanceof PlaceholderType;
+			boolean isBasePairRightPlaceholder = y.getRhsType() instanceof PlaceholderType;
+			if (isBasePairLeftPlaceholder && !isBasePairRightPlaceholder && x.getPairOp() == PairOperator.EQUALSDOT) {
+				lefteqOder.add(x);
+			}
+			else if (isBasePairRightPlaceholder && ((PlaceholderType)y.getRhsType()).getOrCons() == (byte)-1) {
+				lefteqRet.add(x);
+			}
+			else if (x.getPairOp() == PairOperator.SMALLERDOT) {
+				leftleOder.add(x);
+			}
+		}
+
+
+		Set<UnifyPair> righteq = new HashSet<>();
+		Set<UnifyPair> rightle = new HashSet<>();
+		Set<UnifyPair> rightlewc = new HashSet<>();
+		Set<UnifyPair> righteqOder = new HashSet<>();
+		Set<UnifyPair> righteqRet = new HashSet<>();
+		Set<UnifyPair> rightleOder = new HashSet<>();
+		for (var x : right) {
+			boolean isLeftPlaceholder = x.getLhsType() instanceof PlaceholderType;
+			boolean isRightPlaceholder = x.getRhsType() instanceof PlaceholderType;
+			boolean hasPlaceholder = isLeftPlaceholder || isRightPlaceholder;
+
+			if (isLeftPlaceholder && x.getPairOp() == PairOperator.EQUALSDOT) righteq.add(x);
+			if (hasPlaceholder && x.getPairOp() == PairOperator.SMALLERDOT) 	rightle.add(x);
+			if (hasPlaceholder && x.getPairOp() == PairOperator.SMALLERDOTWC) rightlewc.add(x);
+
+			UnifyPair y = x.getGroundBasePair();
+			boolean isBasePairLeftPlaceholder = y.getLhsType() instanceof PlaceholderType;
+			boolean isBasePairRightPlaceholder = y.getRhsType() instanceof PlaceholderType;
+			if (isBasePairLeftPlaceholder && !isBasePairRightPlaceholder && x.getPairOp() == PairOperator.EQUALSDOT) {
+				righteqOder.add(x);
+			}
+			else if (isBasePairRightPlaceholder && ((PlaceholderType)y.getRhsType()).getOrCons() == (byte)-1) {
+				righteqRet.add(x);
+			}
+			else if (x.getPairOp() == PairOperator.SMALLERDOT) {
+				rightleOder.add(x);
+			}
+		}
+
+		//context.logger().info(left.toString());
 		//Fall 2
 		//if (lefteq.iterator().next().getLhsType().getName().equals("AJO")) {
 		//	System.out.print("");
 		//}
 		
 		//ODER-CONSTRAINT
-		Set<UnifyPair> leftBase = left.stream().map(x -> x.getGroundBasePair()).collect(Collectors.toCollection(HashSet::new));
-		Set<UnifyPair> rightBase = right.stream().map(x -> x.getGroundBasePair()).collect(Collectors.toCollection(HashSet::new));
+		// Set<UnifyPair> leftBase = left.stream().map(x -> x.getGroundBasePair()).collect(Collectors.toCollection(HashSet::new));
+		// Set<UnifyPair> rightBase = right.stream().map(x -> x.getGroundBasePair()).collect(Collectors.toCollection(HashSet::new));
 
-		Set<UnifyPair> lefteqOder = left.stream()
-				.filter(x -> { UnifyPair y = x.getGroundBasePair();
-				/*try {
-					((FiniteClosure)fc).logFile.write("leftBase: " + leftBase.toString() +"\n");
-					((FiniteClosure)fc).logFile.write("rightBase: " + rightBase.toString() +"\n\n");
-					((FiniteClosure)fc).logFile.write("left: " + left.toString() +"\n");
-					((FiniteClosure)fc).logFile.write("right: " + right.toString() +"\n\n");
-					((FiniteClosure)fc).logFile.write("y: " + y.toString() +"\n");
-					((FiniteClosure)fc).logFile.write("y.getLhsType() : " + y.getLhsType() .toString() +"\n\n");
-					((FiniteClosure)fc).logFile.write("y.getRhsType(): " + y.getRhsType().toString() +"\n");
-					((FiniteClosure)fc).logFile.write("x.getPairOp(): " + x.getPairOp().toString() +"\n\n");
-					}
-					catch (IOException ie) {
-					}	*/
-	               return (y.getLhsType() instanceof PlaceholderType && 
-	            		   !(y.getRhsType() instanceof PlaceholderType) && 
-	            		   x.getPairOp() == PairOperator.EQUALSDOT);})
-				.collect(Collectors.toCollection(HashSet::new));
 		left.removeAll(lefteqOder);
-		Set<UnifyPair> righteqOder = right.stream()
-				.filter(x -> { UnifyPair y = x.getGroundBasePair(); 
-	               return (y.getLhsType() instanceof PlaceholderType && 
-	            		   !(y.getRhsType() instanceof PlaceholderType) && 
-	            		   x.getPairOp() == PairOperator.EQUALSDOT);})
-				.collect(Collectors.toCollection(HashSet::new));
-		right.removeAll(righteqOder);
-		Set<UnifyPair> lefteqRet = left.stream()
-				.filter(x -> { UnifyPair y = x.getGroundBasePair(); 
-	               return (y.getRhsType() instanceof PlaceholderType && 
-	            		   ((PlaceholderType)y.getRhsType()).getOrCons() == (byte)-1);})
-				.collect(Collectors.toCollection(HashSet::new));
 		left.removeAll(lefteqRet);
-		Set<UnifyPair> righteqRet = right.stream()
-				.filter(x -> { UnifyPair y = x.getGroundBasePair(); 
-	               return (y.getRhsType() instanceof PlaceholderType && 
-	            		   ((PlaceholderType)y.getRhsType()).getOrCons() == (byte)-1);})
-				.collect(Collectors.toCollection(HashSet::new));
+		right.removeAll(righteqOder);
 		right.removeAll(righteqRet);
-		Set<UnifyPair> leftleOder = left.stream()
-				.filter(x -> (x.getPairOp() == PairOperator.SMALLERDOT))
-				.collect(Collectors.toCollection(HashSet::new));
-		Set<UnifyPair> rightleOder = right.stream()
-				.filter(x -> (x.getPairOp() == PairOperator.SMALLERDOT))
-				.collect(Collectors.toCollection(HashSet::new));
 
 		/*
 		synchronized(this) {
@@ -275,89 +266,73 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 		*/
 		
 		
-		Integer compareEq;
+		int compareEq;
 		if (lefteqOder.size() == 1 && righteqOder.size() == 1 && lefteqRet.size() == 1 && righteqRet.size() == 1) {
 			Match m = new Match();
-			if ((compareEq = compareEq(lefteqOder.iterator().next().getGroundBasePair(), righteqOder.iterator().next().getGroundBasePair())) == -1) {
+			compareEq = compareEq(lefteqOder.iterator().next().getGroundBasePair(), righteqOder.iterator().next().getGroundBasePair());
+
+			if (compareEq == -1) {
 				ArrayList<UnifyPair> matchList =
 						rightleOder.stream().map(x -> {
-							UnifyPair leftElem = leftleOder.stream()
+								UnifyPair leftElem = leftleOder.stream()
 														     .filter(y -> y.getGroundBasePair().getLhsType().equals(x.getGroundBasePair().getLhsType()))
-														     .findAny().get(); 
-							return new UnifyPair(x.getRhsType(), leftElem.getRhsType(), PairOperator.EQUALSDOT);})
-											.collect(Collectors.toCollection(ArrayList::new));
-				if (m.match(matchList).isPresent()) {
-					//try { ((FiniteClosure)fc).logFile.write("result1: -1 \n\n"); } catch (IOException ie) {}
-					return -1;
-				}
-				else {
-					//try { ((FiniteClosure)fc).logFile.write("result1: 0 \n\n"); } catch (IOException ie) {}
-					return 0;
-				}
+														     .findAny().orElseThrow();
+								return new UnifyPair(x.getRhsType(), leftElem.getRhsType(), PairOperator.EQUALSDOT);}
+							)
+							.collect(Collectors.toCollection(ArrayList::new));
+
+				return (m.match(matchList).isPresent()) ? -1 : 0;
 			} else if (compareEq == 1) {
 				ArrayList<UnifyPair> matchList =
 						leftleOder.stream().map(x -> {
 							UnifyPair rightElem = rightleOder.stream()
-									                        .filter(y -> 
-									                        	y.getGroundBasePair().getLhsType().equals(x.getGroundBasePair().getLhsType()))
-									                        .findAny().get(); 
-														return new UnifyPair(x.getRhsType(), rightElem.getRhsType(), PairOperator.EQUALSDOT);})
-											.collect(Collectors.toCollection(ArrayList::new));
-				if (m.match(matchList).isPresent()) {
-					//try { ((FiniteClosure)fc).logFile.write("result2: 1 \n\n"); } catch (IOException ie) {}
-					return 1;
-				}
-				else {
-					//try { ((FiniteClosure)fc).logFile.write("result2: 0 \n\n"); } catch (IOException ie) {}
-					return 0;
-				}
+								.filter(y -> y.getGroundBasePair().getLhsType().equals(x.getGroundBasePair().getLhsType()))
+								.findAny().orElseThrow();
+							return new UnifyPair(x.getRhsType(), rightElem.getRhsType(), PairOperator.EQUALSDOT);}
+						)
+						.collect(Collectors.toCollection(ArrayList::new));
+				return (m.match(matchList).isPresent()) ? 1 : 0;
 			} else {
 				/*
-				synchronized(this) {
-					try {
-						((FiniteClosure)fc).logFile.write("leftBase: " + leftBase.toString() +"\n");
-						((FiniteClosure)fc).logFile.write("rightBase: " + rightBase.toString() +"\n\n");
-						((FiniteClosure)fc).logFile.write("left: " + left.toString() +"\n");
-						((FiniteClosure)fc).logFile.write("right: " + right.toString() +"\n\n");
-						((FiniteClosure)fc).logFile.write("lefteqOder: " + lefteqOder.toString() +"\n");
-						((FiniteClosure)fc).logFile.write("righteqOder: " + righteqOder.toString() +"\n\n");
-						((FiniteClosure)fc).logFile.write("lefteqRet: " + lefteqRet.toString() +"\n");
-						((FiniteClosure)fc).logFile.write("righteqRet: " + righteqRet.toString() +"\n\n");
-						((FiniteClosure)fc).logFile.write("leftleOder: " + leftleOder.toString() +"\n");
-						((FiniteClosure)fc).logFile.write("rightleOder: " + rightleOder.toString() +"\n\n");
-						((FiniteClosure)fc).logFile.write("result3: 0 \n\n");
-						((FiniteClosure)fc).logFile.flush();
-					}
-					catch (IOException ie) {
-					}
-				}
+					((FiniteClosure)fc).logFile.write("leftBase: " + leftBase.toString() +"\n");
+					((FiniteClosure)fc).logFile.write("rightBase: " + rightBase.toString() +"\n\n");
+					((FiniteClosure)fc).logFile.write("left: " + left.toString() +"\n");
+					((FiniteClosure)fc).logFile.write("right: " + right.toString() +"\n\n");
+					((FiniteClosure)fc).logFile.write("lefteqOder: " + lefteqOder.toString() +"\n");
+					((FiniteClosure)fc).logFile.write("righteqOder: " + righteqOder.toString() +"\n\n");
+					((FiniteClosure)fc).logFile.write("lefteqRet: " + lefteqRet.toString() +"\n");
+					((FiniteClosure)fc).logFile.write("righteqRet: " + righteqRet.toString() +"\n\n");
+					((FiniteClosure)fc).logFile.write("leftleOder: " + leftleOder.toString() +"\n");
+					((FiniteClosure)fc).logFile.write("rightleOder: " + rightleOder.toString() +"\n\n");
+					((FiniteClosure)fc).logFile.write("result3: 0 \n\n");
+					((FiniteClosure)fc).logFile.flush();
 				*/
 				return 0;
 			}
 		}
 		
 		
-		if (lefteq.size() == 1 && lefteq.iterator().next().getRhsType() instanceof ExtendsType && leftle.size() == 1  && righteq.size() == 0 && rightle.size() == 1) {
+		if (lefteq.size() == 1 && lefteq.iterator().next().getRhsType() instanceof ExtendsType && leftle.size() == 1  && righteq.isEmpty() && rightle.size() == 1) {
 			return 1;
 		}
 		//Fall 2
-		if (lefteq.size() == 0 && leftle.size() == 1 && righteq.size() == 1 && righteq.iterator().next().getRhsType() instanceof ExtendsType && rightle.size() == 1) {
+		if (lefteq.isEmpty() && leftle.size() == 1 && righteq.size() == 1 && righteq.iterator().next().getRhsType() instanceof ExtendsType && rightle.size() == 1) {
 			return -1;
 		}
 		//Fall 3
-		if (lefteq.size() == 1 && lefteq.iterator().next().getRhsType() instanceof SuperType && leftle.size() == 1  && righteq.size() == 0 && rightle.size() == 1) {
+		if (lefteq.size() == 1 && lefteq.iterator().next().getRhsType() instanceof SuperType && leftle.size() == 1  && righteq.isEmpty() && rightle.size() == 1) {
 			return -1;
 		}
 		//Fall 3
-		if (lefteq.size() == 0 && leftle.size() == 1 && righteq.size() == 1 && righteq.iterator().next().getRhsType() instanceof SuperType && rightle.size() == 1) {
+		if (lefteq.isEmpty() && leftle.size() == 1 && righteq.size() == 1 && righteq.iterator().next().getRhsType() instanceof SuperType && rightle.size() == 1) {
 			return 1;
 		}
 		//Fall 5
-		if (lefteq.size() == 1 && leftle.size() == 0 && righteq.size() == 1 && rightle.size() == 1) {
+		if (lefteq.size() == 1 && leftle.isEmpty() && righteq.size() == 1 && rightle.size() == 1) {
 			return -1;
 		}
 		//Fall 5
-		if (lefteq.size() == 1 && leftle.size() == 1 && righteq.size() == 1 && rightle.size() == 0) {
+		if (lefteq.size() == 1 && leftle.size() == 1 && righteq.size() == 1 && rightle.isEmpty()) {
 			return 1;
 		}
 		//Fall 5
@@ -365,7 +340,7 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 			return 0;
 		}
 		// Nur Paare a =. Theta
-		if (leftle.size() == 0 && rightle.size() == 0 && leftlewc.size() == 0 && rightlewc.size() ==0) {
+		if (leftle.isEmpty() && rightle.isEmpty() && leftlewc.isEmpty() && rightlewc.isEmpty()) {
 			Stream<UnifyPair> lseq = lefteq.stream(); //left.filter(x -> (x.getLhsType() instanceof PlaceholderType && x.getPairOp() == PairOperator.EQUALSDOT));
 			Stream<UnifyPair> rseq = righteq.stream(); //right.filter(x -> (x.getLhsType() instanceof PlaceholderType && x.getPairOp() == PairOperator.EQUALSDOT));
 			BinaryOperator<HashMap<UnifyType,UnifyPair>> combiner = (x,y) -> { x.putAll(y); return x;};
@@ -373,13 +348,10 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 			lseq = lseq.filter(x -> !(hm.get(x.getLhsType()) == null));//NOCHMALS UEBERPRUEFEN!!!!
 			lseq = lseq.filter(x -> !x.equals(hm.get(x.getLhsType()))); //Elemente die gleich sind muessen nicht verglichen werden
 			Optional<Integer> si = lseq.map(x -> compareEq(x, hm.get(x.getLhsType()))).reduce((x,y)-> { if (x == y) return x; else return 0; } );
-			if (!si.isPresent()) return 0;
-			else return si.get();
+			return si.orElse(0);
 		}
 		//Fall 1 und 4
-		if (lefteq.size() >= 1 && righteq.size() >= 1 && (leftlewc.size() > 0 || rightlewc.size() > 0)) {
-			if (lefteq.iterator().next().getLhsType().getName().equals("D")) 
-				System.out.print("");
+		if (!lefteq.isEmpty() && !righteq.isEmpty() && (!leftlewc.isEmpty() || !rightlewc.isEmpty())) {
 			//Set<PlaceholderType> varsleft = lefteq.stream().map(x -> (PlaceholderType)x.getLhsType()).collect(Collectors.toCollection(HashSet::new));
 			//Set<PlaceholderType> varsright = righteq.stream().map(x -> (PlaceholderType)x.getLhsType()).collect(Collectors.toCollection(HashSet::new));
 			//filtern des Paares a = Theta, das durch a <. Thata' generiert wurde (nur im Fall 1 relevant)  andere Substitutioen werden rausgefiltert
@@ -400,12 +372,12 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 				//TODO: Hier wird bei Wildcards nicht das richtige compare aufgerufen PL 18-04-20
 				Pair<Integer, Set<UnifyPair>> int_Unifier = compare(lseq.getRhsType(), rseq.getRhsType());
 				Unifier uni = new Unifier();
-				int_Unifier.getValue().get().forEach(x -> uni.add((PlaceholderType) x.getLhsType(), x.getRhsType()));
+				int_Unifier.getValue().orElseThrow().forEach(x -> uni.add((PlaceholderType) x.getLhsType(), x.getRhsType()));
 				if (!lseq.getRhsType().getName().equals(rseq.getRhsType().getName())
-					|| leftlewc.size() == 0 || rightlewc.size() == 0) return int_Unifier.getKey();
+					|| leftlewc.isEmpty() || rightlewc.isEmpty()) return int_Unifier.getKey();
 				else {
-					Set <UnifyPair> lsleuni = leftlewc.stream().map(x -> uni.apply(x)).collect(Collectors.toCollection(HashSet::new));
-					Set <UnifyPair> rsleuni = rightlewc.stream().map(x -> uni.apply(x)).collect(Collectors.toCollection(HashSet::new));
+					Set <UnifyPair> lsleuni = leftlewc.stream().map(uni::apply).collect(Collectors.toCollection(HashSet::new));
+					Set <UnifyPair> rsleuni = rightlewc.stream().map(uni::apply).collect(Collectors.toCollection(HashSet::new));
 					BinaryOperator<HashMap<UnifyType,UnifyPair>> combiner = (x,y) -> { x.putAll(y); return x;};
 				
 					HashMap<UnifyType,UnifyPair> hm;
@@ -422,11 +394,11 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 						Stream<UnifyPair> lslewcstr = lsleuni.stream().filter(x -> !(hm.get(x.getRhsType()) == null));
 						si = lslewcstr.map(x -> fc.compare(x.getLhsType(), hm.get(x.getRhsType()).getLhsType(), PairOperator.SMALLERDOTWC, context)).reduce((x,y)-> { if (x == y) return x; else return 0; } );
 					}
-					if (!si.isPresent()) return 0;
-					else return si.get();
+					return si.orElse(0);
 				}
 			} else {
-				if (leftlewc.size() > 0) {
+				if (!leftlewc.isEmpty()) {
+					/*
 					Set<UnifyPair> subst;
 					subst = leftlewc.stream().map(x -> { 
 						if (x.getLhsType() instanceof PlaceholderType) {
@@ -435,6 +407,7 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 						else {
 							return new UnifyPair(x.getRhsType(), x.getLhsType(), PairOperator.EQUALSDOT);
 						}}).collect(Collectors.toCollection(HashSet::new));
+					 */
 					Unifier uni = new Unifier();
 					lseq = uni.apply(lseq);
 				}

src/main/java/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java

@@ -134,15 +134,15 @@ public final class PlaceholderType extends UnifyType{
 		wildcardable = true;
 	}
 
-	public void setWildcardtable(Boolean wildcardable) {
+	public void setWildcardtable(boolean wildcardable) {
 		this.wildcardable = wildcardable;
 	}
 
-	public Boolean isInnerType() {
+	public boolean isInnerType() {
 		return innerType;
 	}
 
-	public void setInnerType(Boolean innerType) {
+	public void setInnerType(boolean innerType) {
 		this.innerType = innerType;
 	}
 

src/main/java/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java

@@ -32,7 +32,7 @@ public class ReferenceType extends UnifyType implements ISerializableData {
 		return visitor.visit(this, ht);
 	}
 
-	public ReferenceType(String name, Boolean genericTypeVar) {
+	public ReferenceType(String name, boolean genericTypeVar) {
 		super(name, new TypeParams());
 		hashCode = 31 + 17 * typeName.hashCode() + 17 * typeParams.hashCode();
 		this.genericTypeVar = genericTypeVar;

src/main/java/de/dhbwstuttgart/typeinference/unify/model/Unifier.java

@@ -50,8 +50,7 @@ public class Unifier implements Function<UnifyType, UnifyType>, Iterable<Entry<P
 		Unifier tempU = new Unifier(source, target);
 		// Every new substitution must be applied to previously added substitutions
 		// otherwise the unifier needs to be applied multiple times to unify two terms
-		for(PlaceholderType pt : substitutions.keySet())
-			substitutions.put(pt, substitutions.get(pt).apply(tempU));
+		substitutions.replaceAll((pt, ut) -> ut.apply(tempU));
 		substitutions.put(source, target);
 	}
 

src/main/java/de/dhbwstuttgart/typeinference/unify/model/UnifyPair.java

@@ -106,7 +106,11 @@ public class UnifyPair implements IConstraintElement, ISerializableData {
 
 	public SourceLoc getLocation() {
 		if (location != null) return location;
-		else if (basePair != null) return basePair.getLocation();
+		else if (basePair != null) {
+			SourceLoc baseLocation = basePair.getLocation();
+			location = baseLocation;
+			return baseLocation;
+		}
 		return null;
 	}
 		
@@ -201,7 +205,7 @@ public class UnifyPair implements IConstraintElement, ISerializableData {
 			
 	}
 	
-	public Boolean wrongWildcard() {
+	public boolean wrongWildcard() {
 		return lhs.wrongWildcard() || rhs.wrongWildcard();
 	}
 	

src/main/java/de/dhbwstuttgart/typeinference/unify/model/UnifyType.java

@@ -103,7 +103,7 @@ public abstract class UnifyType implements ISerializableData {
     return new ArrayList<>(typeParams.getInvolvedPlaceholderTypes());
 	}
 	
-	public Boolean wrongWildcard() {//default
+	public boolean wrongWildcard() {//default
 		return false;
 	}
 

src/main/java/de/dhbwstuttgart/typeinference/unify/model/WildcardType.java

@@ -42,7 +42,7 @@ public abstract class WildcardType extends UnifyType implements ISerializableDat
 	}
 	
 	@Override
-	public Boolean wrongWildcard () {//This is an error
+	public boolean wrongWildcard () {//This is an error
 		return (wildcardedType instanceof WildcardType);
 	}
 	

src/main/java/de/dhbwstuttgart/util/Logger.java

@@ -1,9 +1,322 @@
 package de.dhbwstuttgart.util;
 
+import com.diogonunes.jcolor.Attribute;
+import de.dhbwstuttgart.core.ConsoleInterface;
+import de.dhbwstuttgart.server.SocketServer;
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.Writer;
+import java.nio.file.Path;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.Arrays;
+import java.util.Objects;
+import java.util.function.Supplier;
+import java.util.stream.Collectors;
+
+import static com.diogonunes.jcolor.Ansi.colorize;
+
 public class Logger {
 
-  public static void print(String s) {
-    System.out.println(s);
+  protected final Writer writer;
+  protected final String prefix;
+
+  public static Logger NULL_LOGGER = new NullLogger();
+  private static DateTimeFormatter timeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
+
+  public Logger() {
+    this(null, "");
   }
 
+  public Logger(String prefix) {
+    this(null, prefix);
+  }
+
+  public Logger(Writer writer, String prefix) {
+    this.prefix = (Objects.equals(prefix, "")) ? "" : "["+prefix+"] ";
+    this.writer = writer;
+  }
+
+  /**
+   * Create a new logger object from the path provided
+   *
+   * @param filePath  The path to the output file. Recommended file extension ".log"
+   * @return          The Logger object for this output file
+   */
+  public static Logger forFile(String filePath, String prefix) {
+    File file = Path.of(filePath).toFile();
+    try {
+      Writer fileWriter = new FileWriter(file);
+      return new Logger(fileWriter, prefix);
+    }
+    catch (IOException exception) {
+      throw new RuntimeException("Failed to created Logger for file " + filePath, exception);
+    }
+  }
+
+  /**
+   * Create a new logger object that inherits the writer of the given logger object
+   *
+   * @param logger    The old logger object, that will provide the writer
+   * @return          The new prefix for the new logger object
+   */
+  public static Logger inherit(Logger logger, String newPrefix) {
+    return new Logger(logger.writer, newPrefix);
+  }
+
+  /**
+   * Tint the prefix in the color of the logLevel
+   * @param logLevel  The logLevel to set the tint to
+   * @return          The tinted string (using ANSI sequences)
+   */
+  protected String getPrefix(LogLevel logLevel) {
+    String fullPrefix = prefix + "[" + logLevel + "] ";
+    return switch (logLevel) {
+      case DEBUG    -> colorize(fullPrefix, Attribute.BRIGHT_MAGENTA_TEXT());
+      case INFO     -> colorize(fullPrefix, Attribute.BLUE_TEXT());
+      case WARNING  -> colorize(fullPrefix, Attribute.YELLOW_TEXT());
+      case ERROR    -> colorize(fullPrefix, Attribute.RED_TEXT());
+      case SUCCESS  -> colorize(fullPrefix, Attribute.GREEN_TEXT());
+    };
+  }
+
+  /**
+   * Print text to the output or error stream, depending on the logLevel
+   * @param s         The string to print
+   * @param logLevel  If logLevel == error, then print to stderr or print to stdout otherwise
+   */
+  protected void print(String s, LogLevel logLevel) {
+    String coloredPrefix = this.getPrefix(logLevel);
+
+    // if we are running the server, prepend the timestamp
+    if(SocketServer.isServerRunning()) {
+      String timestamp = LocalDateTime.now().format(timeFormatter);
+      coloredPrefix = "[" + timestamp + "] " + coloredPrefix;
+    }
+
+    // output to the correct output-stream
+    if (logLevel.isHigherOrEqualTo(LogLevel.ERROR)) {
+      System.out.println(coloredPrefix + s);
+    }
+    else {
+      System.err.println(coloredPrefix + s);
+    }
+  }
+
+  public boolean isLogLevelActive(LogLevel logLevel) {
+    return logLevel.isHigherOrEqualTo(ConsoleInterface.logLevel);
+  }
+
+  /**
+   * Write text to the attached writer if there is any
+   * @param s   The string to print
+   */
+  protected void write(String s) {
+    if (writer != null && ConsoleInterface.writeLogFiles) {
+      // writing to file should only be done when necessary
+      synchronized (writer) {
+        try {
+          writer.write(s);
+        }
+        catch (IOException exception) {
+          throw new RuntimeException("Failed writing to file", exception);
+        }
+      }
+    }
+  }
+
+  /**
+   * Base method for logging a string value. Should mostly be used by the Logger internal functions that
+   * abstract the logLevel away from the parameters
+   *
+   * @hidden Only relevant for the Logger and very special cases with dynamic logLevel
+   * @param s         The text to log
+   * @param logLevel  The logLevel on which the text should be logged
+   */
+  public void log(String s, LogLevel logLevel) {
+    if (isLogLevelActive(logLevel)) {
+      this.print(s, logLevel);
+      this.write(s);
+    }
+  }
+  public void log(Supplier<String> supp, LogLevel logLevel) {
+    if (isLogLevelActive(logLevel)) {
+      this.log(supp.get(), logLevel);
+    }
+  }
+  public void log(Object obj, LogLevel logLevel) {
+    if (isLogLevelActive(logLevel)) {
+      this.log(obj.toString(), logLevel);
+    }
+  }
+
+
+  /**
+   * Output a debug message
+   * @param s The string to log
+   */
+  public void debug(String s) {
+    this.log(s, LogLevel.DEBUG);
+  }
+  public void debug(Object o) {
+    this.log(o, LogLevel.DEBUG);
+  }
+  public void debug(Supplier<String> supp) {
+    this.log(supp, LogLevel.DEBUG);
+  }
+
+  /**
+   * Output an info message
+   * @param s The string to log
+   */
+  public void info(String s) {
+    this.log(s, LogLevel.INFO);
+  }
+  public void info(Object o) {
+    this.log(o, LogLevel.INFO);
+  }
+  public void info(Supplier<String> supp) {
+    this.log(supp, LogLevel.INFO);
+  }
+
+  /**
+   * Output a warning message
+   * @param s The string to log
+   */
+  public void warn(String s) {
+    this.log(s, LogLevel.WARNING);
+  }
+  public void warn(Object o) {
+    this.log(o, LogLevel.WARNING);
+  }
+  public void warn(Supplier<String> supp) {
+    this.log(supp, LogLevel.WARNING);
+  }
+
+  /**
+   * Output an error message
+   * @param s The string to log
+   */
+  public void error(String s) {
+    this.log(s, LogLevel.ERROR);
+  }
+  public void error(Object o) {
+    this.log(o, LogLevel.ERROR);
+  }
+  public void error(Supplier<String> supp) {
+    this.log(supp, LogLevel.ERROR);
+  }
+
+
+  /**
+   * Output a success message
+   * @param s The string to log
+   */
+  public void success(String s) {
+    this.log(s, LogLevel.SUCCESS);
+  }
+  public void success(Object o) {
+    this.log(o, LogLevel.SUCCESS);
+  }
+  public void success(Supplier<String> supp) {
+    this.log(supp, LogLevel.SUCCESS);
+  }
+
+  /**
+   * Special logging function that prints a throwable object and all of its recursive causes (including stacktrace)
+   * as an error
+   *
+   * @param throwable The Throwable object to output
+   */
+  public void exception(Throwable throwable) {
+    // Format the exception output
+    String s = "Exception: " + throwable.getMessage() + "\n" +
+      Arrays.stream(throwable.getStackTrace()).map(stackTraceElement ->
+        " | " + stackTraceElement.toString()
+      ).collect(Collectors.joining("\n"));
+
+    // if there will be a cause printed afterward, announce it with the print of the exception
+    if (throwable.getCause() != null) {
+      s += "\n\nCaused by: ";
+    }
+
+    // print the exception
+    this.error(s);
+
+    // print the cause recursively
+    if (throwable.getCause() != null) {
+      this.exception(throwable.getCause());
+    }
+  }
+
+  public void close() {
+    if (this.writer != null) {
+      try {
+        this.writer.close();
+      }
+      catch (IOException exception) {
+        throw new RuntimeException("Failed to close a loggers writer. Was it maybe already closed? ", exception);
+      }
+    }
+  }
+
+
+  /**
+   * An enum representing the different log levels as integers:
+   * <ul>
+   *  <li>DEBUG: highly specific output only for debugging</li>
+   *  <li>INFO: informational output about the current state of the program</li>
+   *  <li>WARNING: warnings about potential issues or an unexpected state</li>
+   *  <li>ERROR: invalid states, errors and exceptions</li>
+   *  <li>SUCCESS: successfully executed key steps of the program</li>
+   * </ul>
+   */
+  public enum LogLevel {
+    /** Highly specific output only for debugging */
+    DEBUG(0),
+    /** Informational output about the current state of the program */
+    INFO(1),
+    /** Warnings about potential issues or an unexpected state **/
+    WARNING(2),
+    /** Invalid states, errors and exceptions */
+    ERROR(3),
+    /** Successfully executed key steps of the program */
+    SUCCESS(4);
+
+    private final int value;
+    LogLevel(final int newValue) {
+      value = newValue;
+    }
+
+    public boolean isHigherOrEqualTo(LogLevel other) {
+      return this.value >= other.value;
+    }
+
+    public int getValue() {
+      return value;
+    }
+
+    public static LogLevel fromValue(int value) {
+      return switch (value) {
+        case 0 -> LogLevel.DEBUG;
+        case 1 -> LogLevel.INFO;
+        case 2 -> LogLevel.WARNING;
+        case 3 -> LogLevel.ERROR;
+        case 4 -> LogLevel.SUCCESS;
+        default -> throw new RuntimeException("Invalid log level value: " + value);
+      };
+    }
+  }
+
+
+  /**
+   * A special case of logger that will never output anything
+   */
+  private static class NullLogger extends Logger {
+    @Override
+    public void log(String s, LogLevel logLevel) {
+      // Do nothing. Yay
+    }
+  }
 }

src/test/java/TestTypeDeployment.java

@@ -18,7 +18,7 @@ public class TestTypeDeployment {
     public void testTypeDeployment() throws Exception {
         var path = Path.of(System.getProperty("user.dir"), "/resources/bytecode/javFiles/Cycle.jav");
         var file = path.toFile();
-        var compiler = new JavaTXCompiler(file, false);
+        var compiler = new JavaTXCompiler(file);
         var parsedSource = compiler.sourceFiles.get(file);
         var tiResults = compiler.typeInference(file);
         Set<TypeInsert> tips = new HashSet<>();

src/test/java/finiteClosure/SuperInterfacesTest.java

@@ -1,5 +1,6 @@
 package finiteClosure;
 
+import de.dhbwstuttgart.core.JavaTXCompiler;
 import de.dhbwstuttgart.parser.SyntaxTreeGenerator.FCGenerator;
 import de.dhbwstuttgart.syntaxtree.ClassOrInterface;
 import de.dhbwstuttgart.syntaxtree.factory.ASTFactory;
@@ -15,14 +16,14 @@ public class SuperInterfacesTest {
     public void test() throws ClassNotFoundException {
         Collection<ClassOrInterface> classes = new ArrayList<>();
         classes.add(ASTFactory.createClass(TestClass.class));
-        System.out.println(FCGenerator.toFC(classes, ClassLoader.getSystemClassLoader(), new PlaceholderRegistry()));
+        System.out.println(FCGenerator.toFC(classes, ClassLoader.getSystemClassLoader(), JavaTXCompiler.defaultClientPlaceholderRegistry));
     }
 
     @Test
     public void testGeneric() throws ClassNotFoundException {
         Collection<ClassOrInterface> classes = new ArrayList<>();
         classes.add(ASTFactory.createClass(TestClassGeneric.class));
-        System.out.println(FCGenerator.toFC(classes, ClassLoader.getSystemClassLoader(), new PlaceholderRegistry()));
+        System.out.println(FCGenerator.toFC(classes, ClassLoader.getSystemClassLoader(), JavaTXCompiler.defaultClientPlaceholderRegistry));
     }
 }
 

src/test/java/server/PacketExampleData.java

@@ -18,6 +18,7 @@ import de.dhbwstuttgart.typeinference.unify.model.SuperType;
 import de.dhbwstuttgart.typeinference.unify.model.TypeParams;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyType;
+import de.dhbwstuttgart.util.Logger;
 import java.io.Writer;
 import java.util.HashSet;
 import java.util.List;
@@ -84,13 +85,12 @@ class PacketExampleData {
 
   static UnifyContext createTestContext() {
     var placeholderRegistry = new PlaceholderRegistry();
-    var nullWriter = Writer.nullWriter();
-    return new UnifyContext(nullWriter, false, true,
+    return new UnifyContext(Logger.NULL_LOGGER, true,
       new UnifyResultModel(
         new ConstraintSet<>(),
         new FiniteClosure(
           new HashSet<>(),
-          nullWriter,
+          Logger.NULL_LOGGER,
           placeholderRegistry)),
       new UnifyTaskModel(),
       ForkJoinPool.commonPool(),

src/test/java/server/ServerTest.java

@@ -0,0 +1,152 @@
+package server;
+
+import de.dhbwstuttgart.core.ConsoleInterface;
+import de.dhbwstuttgart.core.JavaTXCompiler;
+import de.dhbwstuttgart.core.JavaTXServer;
+import de.dhbwstuttgart.environment.CompilationEnvironment;
+import de.dhbwstuttgart.server.SocketClient;
+import de.dhbwstuttgart.server.packet.SetAutoclosePacket;
+import de.dhbwstuttgart.server.packet.UnifyRequestPacket;
+import de.dhbwstuttgart.syntaxtree.ClassOrInterface;
+import de.dhbwstuttgart.syntaxtree.factory.ASTFactory;
+import de.dhbwstuttgart.syntaxtree.factory.UnifyTypeFactory;
+import de.dhbwstuttgart.typeinference.constraints.ConstraintSet;
+import de.dhbwstuttgart.typeinference.constraints.Pair;
+import de.dhbwstuttgart.typeinference.result.ResultSet;
+import de.dhbwstuttgart.typeinference.unify.PlaceholderRegistry;
+import de.dhbwstuttgart.typeinference.unify.TypeUnify;
+import de.dhbwstuttgart.typeinference.unify.UnifyContext;
+import de.dhbwstuttgart.typeinference.unify.UnifyResultListenerImpl;
+import de.dhbwstuttgart.typeinference.unify.UnifyResultModel;
+import de.dhbwstuttgart.typeinference.unify.UnifyTaskModel;
+import de.dhbwstuttgart.typeinference.unify.model.FiniteClosure;
+import de.dhbwstuttgart.typeinference.unify.model.PlaceholderType;
+import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
+import de.dhbwstuttgart.typeinference.unify.model.UnifyType;
+import de.dhbwstuttgart.util.Logger;
+import java.io.File;
+import java.io.IOException;
+import java.io.Writer;
+import java.nio.file.Path;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.stream.Collectors;
+import org.junit.Ignore;
+import org.junit.Test;
+import targetast.TestCodegen;
+import static org.junit.Assert.*;
+
+@Ignore("Server tests create huge overhead, so they are ignored until required")
+public class ServerTest {
+
+  public ServerTest() {
+    ConsoleInterface.unifyServerUrl = Optional.of("ws://localhost:5000");
+  }
+
+  @Test
+  public void checkServer_Scalar() throws IOException, ClassNotFoundException {
+    compareLocalAndServerResult("Scalar.jav");
+  }
+
+  @Test
+  public void checkServer_Matrix() throws IOException, ClassNotFoundException {
+    compareLocalAndServerResult("Matrix.jav");
+  }
+
+  protected void compareLocalAndServerResult(final String filename) throws IOException, ClassNotFoundException {
+    File file = Path.of(TestCodegen.path.toString(), filename).toFile();
+
+    // get information from the compiler
+    JavaTXCompiler compiler = new JavaTXCompiler(List.of(file));
+
+    // NOW: simulate the call to method typeInference. Once via server and once locally
+    // if everything works, they should neither interfere with each other nor differ in their result
+
+    // get the values from the compiler
+    PlaceholderRegistry placeholderRegistry = JavaTXCompiler.defaultClientPlaceholderRegistry; //new PlaceholderRegistry();
+    ConstraintSet<Pair> cons = compiler.getConstraints(file);
+    ConstraintSet<UnifyPair> unifyCons = UnifyTypeFactory.convert(compiler, cons, placeholderRegistry);
+    unifyCons = unifyCons.map(ServerTest::distributeInnerVars);
+
+    FiniteClosure finiteClosure = UnifyTypeFactory.generateFC(
+      ServerTest.getAllClasses(compiler, file).stream().toList(),
+      Logger.NULL_LOGGER,
+      compiler.classLoader,
+      compiler,
+      placeholderRegistry
+    );
+    UnifyTaskModel usedTasks = new UnifyTaskModel();
+
+
+
+    // create the server
+    JavaTXServer server = new JavaTXServer(5000);
+    try (ExecutorService executor = Executors.newSingleThreadExecutor()) {
+      // run the server in a separate thread
+      executor.submit(server::listen);
+    }
+
+    // run the unification on the server
+    PlaceholderRegistry prCopy = JavaTXCompiler.defaultClientPlaceholderRegistry.deepClone();
+    UnifyResultModel urm = new UnifyResultModel(cons, finiteClosure);
+    UnifyContext context = new UnifyContext(Logger.NULL_LOGGER, true, urm, usedTasks, prCopy);
+    SocketClient.execute(SetAutoclosePacket.create());
+    List<ResultSet> serverResult = SocketClient.executeAndGet(
+      UnifyRequestPacket.create(finiteClosure, cons, unifyCons, context.placeholderRegistry())
+    ).getResultSet(context);
+
+    // close the server
+    server.forceStop();
+
+    // run the unification on the client (do this second, because it changes the initial placeholder registry)
+    UnifyResultListenerImpl li = new UnifyResultListenerImpl();
+    urm.addUnifyResultListener(li);
+    TypeUnify.unifyParallel(unifyCons.getUndConstraints(), unifyCons.getOderConstraints(), finiteClosure, context);
+    List<ResultSet> clientResult = li.getResults();
+
+
+    // create the bytecode from both results
+    var sf = compiler.sourceFiles.get(file);
+    var serverBytecode = compiler.generateBytecode(sf, serverResult);
+    var localBytecode = compiler.generateBytecode(sf, clientResult);
+
+    // test if the generated code is the same
+    for (var serverEntry : serverBytecode.entrySet()) {
+      var serverBytes = serverEntry.getValue();
+      var localBytes = localBytecode.get(serverEntry.getKey());
+      assertArrayEquals(serverBytes, localBytes);
+    }
+  }
+
+
+  protected static UnifyPair distributeInnerVars(UnifyPair x) {
+    UnifyType lhs, rhs;
+    if (((lhs = x.getLhsType()) instanceof PlaceholderType) && ((rhs = x.getRhsType()) instanceof PlaceholderType) && (((PlaceholderType) lhs).isInnerType() || ((PlaceholderType) rhs).isInnerType())) {
+      ((PlaceholderType) lhs).setInnerType(true);
+      ((PlaceholderType) rhs).setInnerType(true);
+    }
+    return x;
+  }
+
+  protected static Set<ClassOrInterface> getAllClasses(JavaTXCompiler compiler, File file)
+    throws ClassNotFoundException, IOException
+  {
+    var sf = compiler.sourceFiles.get(file);
+    Set<ClassOrInterface> allClasses = new HashSet<>();
+    allClasses.addAll(compiler.getAvailableClasses(sf));
+    allClasses.addAll(sf.getClasses());
+    var newClasses = CompilationEnvironment.loadDefaultPackageClasses(sf.getPkgName(), file, compiler).stream().map(ASTFactory::createClass).collect(Collectors.toSet());
+    for (var clazz : newClasses) {
+      // Don't load classes that get recompiled
+      if (sf.getClasses().stream().anyMatch(nf -> nf.getClassName().equals(clazz.getClassName())))
+        continue;
+      if (allClasses.stream().noneMatch(old -> old.getClassName().equals(clazz.getClassName())))
+        allClasses.add(clazz);
+    }
+    return allClasses;
+  }
+}