public static void main(String[] args) {
    HelloCollision app = new HelloCollision();
    app.start();
  }
Example 9 - How to make walls and floors solid.
This collision code uses Physics and a custom Action Listener.
@author normen, with edits by Zathras
jme3-examples/src/main/java/jme3test/helloworld/HelloCollision.java