diff --git a/src/de/dhbwstuttgart/typeinference/unify/freshPlaceholder.java b/src/de/dhbwstuttgart/typeinference/unify/freshPlaceholder.java
index 45ccb6bb..69870bd5 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/freshPlaceholder.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/freshPlaceholder.java
@@ -1,47 +1,15 @@
 package de.dhbwstuttgart.typeinference.unify;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.HashSet;
+
 import java.util.HashMap;
-import java.util.stream.Collectors;
 
-import de.dhbwstuttgart.typeinference.unify.interfaces.UnifyTypeVisitor;
-import de.dhbwstuttgart.typeinference.unify.model.ExtendsType;
-import de.dhbwstuttgart.typeinference.unify.model.FunNType;
 import de.dhbwstuttgart.typeinference.unify.model.PlaceholderType;
-import de.dhbwstuttgart.typeinference.unify.model.ReferenceType;
-import de.dhbwstuttgart.typeinference.unify.model.SuperType;
-import de.dhbwstuttgart.typeinference.unify.model.TypeParams;
 
-public class freshPlaceholder implements UnifyTypeVisitor {
 
-	public ReferenceType visit(ReferenceType refty, HashMap<PlaceholderType,PlaceholderType> ht) {
-		return new ReferenceType(refty.getName(),
-				new TypeParams(
-						Arrays.stream(refty.getTypeParams().get())
-						.map(x -> x.accept(this, ht))
-						.collect(Collectors.toCollection(ArrayList::new))));
-	}
-	
+public class freshPlaceholder extends visitUnifyTypeVisitor<HashMap<PlaceholderType,PlaceholderType>> {
+
+	@Override
 	public PlaceholderType visit(PlaceholderType phty, HashMap<PlaceholderType,PlaceholderType> ht) {
 		return ht.get(phty);
-	}
-	
-	public FunNType visit(FunNType funnty, HashMap<PlaceholderType,PlaceholderType> ht) {
-		return FunNType.getFunNType(
-				new TypeParams(
-						Arrays.stream(funnty.getTypeParams().get())
-						.map(x -> x.accept(this, ht))
-						.collect(Collectors.toCollection(ArrayList::new)))
-				);	
-	}
-	
-	public SuperType visit(SuperType suty, HashMap<PlaceholderType,PlaceholderType> ht) {
-		return new SuperType(suty.getWildcardedType().accept(this, ht));
-	}
-	
-	public ExtendsType visit(ExtendsType extty, HashMap<PlaceholderType,PlaceholderType> ht) {
-		return new ExtendsType(extty.getWildcardedType().accept(this, ht));
-	}
+	}	
 }
diff --git a/src/de/dhbwstuttgart/typeinference/unify/interfaces/UnifyTypeVisitor.java b/src/de/dhbwstuttgart/typeinference/unify/interfaces/UnifyTypeVisitor.java
index bf435f9c..8d06b3e1 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/interfaces/UnifyTypeVisitor.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/interfaces/UnifyTypeVisitor.java
@@ -8,16 +8,16 @@ import de.dhbwstuttgart.typeinference.unify.model.PlaceholderType;
 import de.dhbwstuttgart.typeinference.unify.model.ReferenceType;
 import de.dhbwstuttgart.typeinference.unify.model.SuperType;
 
-public interface UnifyTypeVisitor {
+public interface UnifyTypeVisitor<T> {
 
-	public ReferenceType visit(ReferenceType refty, HashMap<PlaceholderType,PlaceholderType> ht);
+	public ReferenceType visit(ReferenceType refty, T ht);
 	
-	public PlaceholderType visit(PlaceholderType phty, HashMap<PlaceholderType,PlaceholderType> ht);
+	public PlaceholderType visit(PlaceholderType phty, T ht);
 	
-	public FunNType visit(FunNType funnty, HashMap<PlaceholderType,PlaceholderType> ht);
+	public FunNType visit(FunNType funnty, T ht);
 	
-	public SuperType visit(SuperType suty, HashMap<PlaceholderType,PlaceholderType> ht);
+	public SuperType visit(SuperType suty, T ht);
 	
-	public ExtendsType visit(ExtendsType extty, HashMap<PlaceholderType,PlaceholderType> ht);
+	public ExtendsType visit(ExtendsType extty, T ht);
 
 }
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/ExtendsType.java b/src/de/dhbwstuttgart/typeinference/unify/model/ExtendsType.java
index a97977c5..a7ff3af8 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/ExtendsType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/ExtendsType.java
@@ -13,7 +13,7 @@ import de.dhbwstuttgart.typeinference.unify.interfaces.UnifyTypeVisitor;
  */
 public final class ExtendsType extends WildcardType {
 	
-	public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht) {
+	public <T> UnifyType accept(UnifyTypeVisitor<T> visitor, T ht) {
 		return visitor.visit(this, ht);
 	}
 	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java b/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java
index dd96dedd..37ec79d5 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java
@@ -12,7 +12,7 @@ import de.dhbwstuttgart.typeinference.unify.interfaces.UnifyTypeVisitor;
  */
 public class FunNType extends UnifyType {
 
-	public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht) {
+	public <T> UnifyType accept(UnifyTypeVisitor<T> visitor, T ht) {
 		return visitor.visit(this, ht);
 	}
 	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java b/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java
index d9fd6699..21e8a66b 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java
@@ -65,7 +65,7 @@ public final class PlaceholderType extends UnifyType{
 		IsGenerated = isGenerated;
 	}
 	
-	public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht) {
+	public <T> UnifyType accept(UnifyTypeVisitor<T> visitor, T ht) {
 		return visitor.visit(this, ht);
 	}
 	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java b/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java
index 133a87ed..81f6c3b3 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/ReferenceType.java
@@ -19,7 +19,7 @@ public final class ReferenceType extends UnifyType {
 	private final int hashCode;
 	
 
-	public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht) {
+	public <T> UnifyType accept(UnifyTypeVisitor<T> visitor, T ht) {
 		return visitor.visit(this, ht);
 	}
 	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/SuperType.java b/src/de/dhbwstuttgart/typeinference/unify/model/SuperType.java
index 0b98c159..53762f86 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/SuperType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/SuperType.java
@@ -12,7 +12,7 @@ import de.dhbwstuttgart.typeinference.unify.interfaces.UnifyTypeVisitor;
  */
 public final class SuperType extends WildcardType {
 	
-	public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht) {
+	public <T> UnifyType accept(UnifyTypeVisitor<T> visitor, T ht) {
 		return visitor.visit(this, ht);
 	}
 	
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/UnifyType.java b/src/de/dhbwstuttgart/typeinference/unify/model/UnifyType.java
index 16986d65..555083e8 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/UnifyType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/UnifyType.java
@@ -37,7 +37,7 @@ public abstract class UnifyType {
 	}
 	
 
-	abstract public UnifyType accept(UnifyTypeVisitor visitor, HashMap<PlaceholderType,PlaceholderType> ht); 
+	abstract public <T> UnifyType accept(UnifyTypeVisitor<T> visitor, T ht); 
 	
 	/**
 	 * Returns the name of the type.