Andengine Multi dex files define Vector2

Question

hope you can help me with my Problem. I tried to use Box2D Physics extension and to get how it works i used AndEngine for Android Game Development Cookbook (Chapter 6).

But now there's an Error when i want to Run the Example. In Console it says:

[2014-04-12 14:45:12 - Dex Loader] Unable to execute dex: Multiple dex files define Lcom/badlogic/gdx/math/Vector2;
[2014-04-12 14:45:12 - engine] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lcom/badlogic/gdx/math/Vector2;

Solution:

In AndEngine -> src -> com.badlogic.gdx.math there is a file named Vector2.java In AndEnginePhysicsBox2DExtension -> src -> com.badlogic.gdx.math there is a file named Vector2.java too ... delete the last one and the Problem is solved!

Answer 1

IF you have an external .jar in my libs folder called gson-2.2.2.jar but for some reason there were two of them, gson-2.2.2.jar and gson-2.2.2.jar(1), I simply delete the second one and try then your project built fine again. Hope it helps..