diff --git a/src/de/dhbwstuttgart/environment/CompilationEnvironment.java b/src/de/dhbwstuttgart/environment/CompilationEnvironment.java
index 44754e7c..3d450183 100644
--- a/src/de/dhbwstuttgart/environment/CompilationEnvironment.java
+++ b/src/de/dhbwstuttgart/environment/CompilationEnvironment.java
@@ -62,7 +62,7 @@ public class CompilationEnvironment {
 			}
 		//URLClassLoader loader = new URLClassLoader(new URL[0], cl);
 		//librarys = Arrays.asList(loader.getURLs());
-		
+
 		this.sourceFiles = sourceFiles;
         this.packageCrawler = new PackageCrawler(librarys);
 	}
diff --git a/src/de/dhbwstuttgart/parser/SyntaxTreeGenerator/SyntaxTreeGenerator.java b/src/de/dhbwstuttgart/parser/SyntaxTreeGenerator/SyntaxTreeGenerator.java
index b681d9c3..ed96d2e6 100644
--- a/src/de/dhbwstuttgart/parser/SyntaxTreeGenerator/SyntaxTreeGenerator.java
+++ b/src/de/dhbwstuttgart/parser/SyntaxTreeGenerator/SyntaxTreeGenerator.java
@@ -164,7 +164,12 @@ public class SyntaxTreeGenerator{
         modifiers += newModifier;
       }
     }
-    JavaClassName name = reg.getName(ctx.Identifier().getText());
+    String className = this.pkgName + (this.pkgName.length()>0?".":"") + ctx.Identifier().getText();
+    JavaClassName name = reg.getName(className);
+    if(! name.toString().equals(className)){
+      throw new TypeinferenceException("Name " + className + " bereits vorhanden in " + reg.getName(className).toString()
+              ,ctx.getStart());
+    }
     GenericsRegistry generics = createGenerics(ctx.typeParameters(), name, "", reg, new GenericsRegistry(globalGenerics));
     Token offset = ctx.getStart();
     GenericDeclarationList genericClassParameters;
diff --git a/test/javFiles/Vector.jav b/test/javFiles/Vector.jav
index 1ea1ac41..ef3533a6 100644
--- a/test/javFiles/Vector.jav
+++ b/test/javFiles/Vector.jav
@@ -1,6 +1,6 @@
 import java.util.Vector;
 
-class Vector{
+class MyVector{
 
 id(x){
   return id2(x);