diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
index be9471c0..975ff37c 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
@@ -179,7 +179,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 			catch (IOException e) { 
 				System.err.println("log-File nicht vorhanden");
 			}
-			/* Abbruchtest
+			/*Abbruchtest
 			if (thNo > 10) {
 				System.out.println("cancel");
 				usedTasks.cancel();
@@ -1110,9 +1110,6 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 				if (!isUndefinedPairSetSet(res) && isUndefinedPairSetSet(result)) {
 					//wenn korrektes Ergebnis gefunden alle Fehlerfaelle loeschen
 					result = res;
-					if (res.iterator().next() instanceof WildcardType) {
-						System.out.println("");
-					}
 				}
 				else { 
 					if ((isUndefinedPairSetSet(res) && isUndefinedPairSetSet(result))
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyTaskModel.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyTaskModel.java
index 5b70eff8..e60054f0 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyTaskModel.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyTaskModel.java
@@ -6,11 +6,11 @@ public class UnifyTaskModel {
 
 	ArrayList<TypeUnifyTask> usedTasks = new ArrayList<>();
 	
-	public void add(TypeUnifyTask t) {
+	public synchronized void add(TypeUnifyTask t) {
 		usedTasks.add(t);
 	}
     
-    public void cancel() {
+    public synchronized void cancel() {
     	for(TypeUnifyTask t : usedTasks) {
     		t.myCancel(true);
     	}