If you are using the old LibGDX project generation (gdx-setup-ui.jar) method, then you'll need to add gdx-bullet.jar to your main project. Alternatively, you can add the gdx-bullet project to the projects of the build path of your main project. For your desktop project, you'll need to add the gdx-bullet-natives.jar file to the libraries. For your android project, you'll need to copy the armeabi/libgdx-bullet.so file and armeabi-v7a/libgdx-bullet.so file to the libs folder in your android project.

Bullet isn't supported for GWT at the moment. Alternatively, we can use the LibGDX Gradle Project Setup (gdx-setup.jar) tool where Bullet will be linked altogether and you don't have to worry about it.

Open the gdx-setup.jar file and enter the following details: