diff --git a/src/de/dhbwstuttgart/typinference/unify/model/ExtendsType.java b/src/de/dhbwstuttgart/typinference/unify/model/ExtendsType.java
index c01ff5d4c..d648c249a 100644
--- a/src/de/dhbwstuttgart/typinference/unify/model/ExtendsType.java
+++ b/src/de/dhbwstuttgart/typinference/unify/model/ExtendsType.java
@@ -4,10 +4,11 @@ import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 
-public class ExtendsType extends Type {
+public final class ExtendsType extends Type {
 	private Type extendedType;
 	
 	public ExtendsType(Type extendedType) {
+		super("? extends " + extendedType.getTypeParams(), extendedType.getTypeParams());
 		this.extendedType = extendedType;
 	}
 	
diff --git a/src/de/dhbwstuttgart/typinference/unify/model/PlaceholderType.java b/src/de/dhbwstuttgart/typinference/unify/model/PlaceholderType.java
index 48cf2e6f2..dd40ab23b 100644
--- a/src/de/dhbwstuttgart/typinference/unify/model/PlaceholderType.java
+++ b/src/de/dhbwstuttgart/typinference/unify/model/PlaceholderType.java
@@ -4,10 +4,10 @@ import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 
-public class PlaceholderType extends Type{
+public final class PlaceholderType extends Type{
 	
 	public PlaceholderType(String name) {
-		typeName = name;
+		super(name);
 	}
 
 	@Override
diff --git a/src/de/dhbwstuttgart/typinference/unify/model/SimpleType.java b/src/de/dhbwstuttgart/typinference/unify/model/SimpleType.java
index 199c6518e..292289779 100644
--- a/src/de/dhbwstuttgart/typinference/unify/model/SimpleType.java
+++ b/src/de/dhbwstuttgart/typinference/unify/model/SimpleType.java
@@ -4,10 +4,9 @@ import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 
-public class SimpleType extends Type {
+public final class SimpleType extends Type {
 	public SimpleType(String name, Type... typeParams) {
-		this.typeName = name;
-		this.typeParams = new TypeParams(typeParams);
+		super(name, new TypeParams(typeParams));
 	}
 
 	@Override
diff --git a/src/de/dhbwstuttgart/typinference/unify/model/SuperType.java b/src/de/dhbwstuttgart/typinference/unify/model/SuperType.java
index 5a734621e..2148e0dfa 100644
--- a/src/de/dhbwstuttgart/typinference/unify/model/SuperType.java
+++ b/src/de/dhbwstuttgart/typinference/unify/model/SuperType.java
@@ -4,11 +4,12 @@ import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 
-public class SuperType extends Type {
+public final class SuperType extends Type {
 	
 	private Type superedType;
 	
 	public SuperType(Type superedType) {
+		super("? extends " + superedType.getName(), superedType.getTypeParams());
 		this.superedType = superedType;
 	}
 	
diff --git a/src/de/dhbwstuttgart/typinference/unify/model/Type.java b/src/de/dhbwstuttgart/typinference/unify/model/Type.java
index dc5a9d915..3da9dbcd0 100644
--- a/src/de/dhbwstuttgart/typinference/unify/model/Type.java
+++ b/src/de/dhbwstuttgart/typinference/unify/model/Type.java
@@ -1,17 +1,22 @@
 package de.dhbwstuttgart.typinference.unify.model;
 
-import java.util.Arrays;
 import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 
 public abstract class Type {
 	
-	protected String typeName = "";
-	protected TypeParams typeParams;
+	protected final String typeName;
+	protected final TypeParams typeParams;
 	
-	public Type() {
-		typeParams = new TypeParams();
+	protected Type(String name, Type... typeParams) {
+		typeName = name;
+		this.typeParams = new TypeParams(typeParams);
+	}
+	
+	protected Type(String name, TypeParams p) {
+		typeName = name;
+		typeParams = p;
 	}
 	
 	public String getName() {
diff --git a/src/de/dhbwstuttgart/typinference/unify/model/TypeParams.java b/src/de/dhbwstuttgart/typinference/unify/model/TypeParams.java
index c89b207d4..c6e3ee005 100644
--- a/src/de/dhbwstuttgart/typinference/unify/model/TypeParams.java
+++ b/src/de/dhbwstuttgart/typinference/unify/model/TypeParams.java
@@ -3,8 +3,10 @@ package de.dhbwstuttgart.typinference.unify.model;
 import java.util.Arrays;
 import java.util.Iterator;
 
-public class TypeParams implements Iterable<Type>{
-	private Type[] typeParams;
+import de.dhbwstuttgart.typeinference.unifynew.Unifier;
+
+public final class TypeParams implements Iterable<Type>{
+	private final Type[] typeParams;
 	
 	public TypeParams(Type... types) {
 		typeParams = types;
@@ -26,8 +28,20 @@ public class TypeParams implements Iterable<Type>{
 		return typeParams.length == 0;
 	}
 	
-	public Type[] asArray() {
-		return typeParams;
+	public void apply(Unifier u) {
+		for(int i = 0; i < typeParams.length; i++)
+			typeParams[i] = u.apply(typeParams[i]);
+	}
+	
+	public boolean contains(Type t) {
+		for(Type t1 : typeParams)
+			if(t1.equals(t1)) 
+				return true;
+		return false;
+	}
+	
+	public Type get(int i) {
+		return typeParams[i];
 	}
 
 	@Override