diff --git a/resources/bytecode/javFiles/Op1.jav b/resources/bytecode/javFiles/Op1.jav
index 800f58b8..426569dc 100644
--- a/resources/bytecode/javFiles/Op1.jav
+++ b/resources/bytecode/javFiles/Op1.jav
@@ -1,11 +1,9 @@
-public class Op1{
-	public Op1() {
-		
-		Runnable lam = () -> {
-				String test = "";
-					String b = "b";
-					test = b;
-				System.out.println(test);};
-		//lam.run();
+import java.lang.Boolean;
+
+public class Op1 {
+	public m() {
+		var b = false;
+		var c = !b;
+		return c;
 	}
 }
\ No newline at end of file
diff --git a/src/main/java/de/dhbwstuttgart/parser/SyntaxTreeGenerator/StatementGenerator.java b/src/main/java/de/dhbwstuttgart/parser/SyntaxTreeGenerator/StatementGenerator.java
index 26c9728c..7bdb0489 100644
--- a/src/main/java/de/dhbwstuttgart/parser/SyntaxTreeGenerator/StatementGenerator.java
+++ b/src/main/java/de/dhbwstuttgart/parser/SyntaxTreeGenerator/StatementGenerator.java
@@ -996,6 +996,9 @@ public class StatementGenerator {
             ret = new UnaryExpr(UnaryExpr.Operation.PREDECREMENT, expr, TypePlaceholder.fresh(op), op);
             ret.setStatement();
             return ret;
+        } else if (op.getText().equals("!")) {
+            ret = new UnaryExpr(UnaryExpr.Operation.NOT, expr, TypePlaceholder.fresh(op), op);
+            return ret;
         } else {
             throw new NotImplementedException();
         }
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/typeAlgo/TYPEStmt.java b/src/main/java/de/dhbwstuttgart/typeinference/typeAlgo/TYPEStmt.java
index f4df7a50..4cf55ce9 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/typeAlgo/TYPEStmt.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/typeAlgo/TYPEStmt.java
@@ -245,6 +245,9 @@ public class TYPEStmt implements StatementVisitor {
             constraintsSet.addUndConstraint(new Pair(unaryExpr.expr.getType(), number, PairOperator.SMALLERNEQDOT, loc(unaryExpr.getOffset())));
             // The type of the postfix increment expression is the type of the variable
             constraintsSet.addUndConstraint(new Pair(unaryExpr.expr.getType(), unaryExpr.getType(), PairOperator.EQUALSDOT, loc(unaryExpr.getOffset())));
+        } else if (unaryExpr.operation == UnaryExpr.Operation.NOT) {
+            constraintsSet.addUndConstraint(new Pair(unaryExpr.expr.getType(), unaryExpr.getType(), PairOperator.EQUALSDOT, loc(unaryExpr.getOffset())));
+            constraintsSet.addUndConstraint(new Pair(unaryExpr.expr.getType(), new RefType(ASTFactory.createClass(java.lang.Boolean.class).getClassName(), new NullToken()), PairOperator.EQUALSDOT, loc(unaryExpr.getOffset())));
         } else {
             throw new NotImplementedException();
         }
diff --git a/src/test/java/TestComplete.java b/src/test/java/TestComplete.java
index 06a99ca7..671e9529 100644
--- a/src/test/java/TestComplete.java
+++ b/src/test/java/TestComplete.java
@@ -837,6 +837,14 @@ public class TestComplete {
         assertEquals(clazz.getSuperclass().getDeclaredField("x").get(instance), 3);
     }
 
+    @Test
+    public void testOperators() throws Exception {
+        var classFiles = generateClassFiles(new ByteArrayClassLoader(), "Op1.jav");
+        var clazz = classFiles.get("Op1");
+        var instance = clazz.getDeclaredConstructor().newInstance();
+        assertEquals(clazz.getDeclaredMethod("m").invoke(instance), true);
+    }
+
     @Ignore("Not implemented")
     @Test
     public void testStringConcat() throws Exception {