diff --git a/src/main/java/de/dhbwstuttgart/inferWildcards/ReplaceTypeparamVisitor.java b/src/main/java/de/dhbwstuttgart/inferWildcards/ReplaceTypeparamVisitor.java
new file mode 100644
index 00000000..808f9579
--- /dev/null
+++ b/src/main/java/de/dhbwstuttgart/inferWildcards/ReplaceTypeparamVisitor.java
@@ -0,0 +1,40 @@
+package de.dhbwstuttgart.inferWildcards;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import de.dhbwstuttgart.parser.NullToken;
+import de.dhbwstuttgart.syntaxtree.AbstractASTWalker;
+import de.dhbwstuttgart.syntaxtree.type.RefType;
+import de.dhbwstuttgart.syntaxtree.type.RefTypeOrTPHOrWildcardOrGeneric;
+import de.dhbwstuttgart.syntaxtree.type.TypePlaceholder;
+
+public class ReplaceTypeparamVisitor
+	extends AbstractASTWalker
+{
+
+	private final Map<TypePlaceholder, RefTypeOrTPHOrWildcardOrGeneric> tphMap;
+	
+	public ReplaceTypeparamVisitor () {
+		this.tphMap = new HashMap<>();
+	}
+
+	@Override
+	public void visit (RefType refType) {
+		if (!refType.getParaList().isEmpty()) {
+			System.out.println("Type: " + refType);
+			generateTypePlaceholder(refType);
+		}
+		super.visit(refType);
+	}
+
+	private TypePlaceholder generateTypePlaceholder (RefType t) {
+		TypePlaceholder tph = TypePlaceholder.fresh(new NullToken());
+		tphMap.put(tph, t);
+		return tph;
+	}
+
+	public Map<TypePlaceholder, RefTypeOrTPHOrWildcardOrGeneric> getTphMap () {
+		return tphMap;
+	}
+}
diff --git a/src/test/java/inferWildcards/TestInferWildcardsJavaTx.java b/src/test/java/inferWildcards/TestInferWildcardsJavaTx.java
index b5b7818a..8d66011f 100644
--- a/src/test/java/inferWildcards/TestInferWildcardsJavaTx.java
+++ b/src/test/java/inferWildcards/TestInferWildcardsJavaTx.java
@@ -1,6 +1,7 @@
 package inferWildcards;
 
 import java.io.File;
+import java.util.Map;
 
 import javax.tools.JavaCompiler;
 import javax.tools.StandardJavaFileManager;
@@ -10,6 +11,8 @@ import org.junit.Before;
 import org.junit.Test;
 
 import de.dhbwstuttgart.core.JavaTXCompiler;
+import de.dhbwstuttgart.inferWildcards.ReplaceTypeparamVisitor;
+import de.dhbwstuttgart.syntaxtree.SourceFile;
 import de.dhbwstuttgart.typeinference.constraints.ConstraintSet;
 import de.dhbwstuttgart.typeinference.constraints.Pair;
 
@@ -31,8 +34,17 @@ public class TestInferWildcardsJavaTx
 		File[] files1 = { new File(resourcePath + "/TestClassWildcards.java") };
 
 		JavaTXCompiler javaTXCompiler = new JavaTXCompiler(files1);
+
+		// Manipulate AST
+		Map<File, SourceFile> sourceFiles = javaTXCompiler.getSourceFiles();
+		ReplaceTypeparamVisitor visitor = new ReplaceTypeparamVisitor();
+		sourceFiles.entrySet().forEach(e -> e.getValue().accept(visitor));
+		System.out.println(visitor.getTphMap());
+
+		// Constraints
 		ConstraintSet<Pair> constraints = javaTXCompiler.getConstraints();
-		System.out.println(constraints);
+
+		// System.out.println(constraints);
 	}
 
 }