Suggested platform/tools for rapid game development and game prototyping

public class HelloWorld extends SimpleGame{
 public static void main(String[] args) {
  HelloWorld app = new HelloWorld(); // Create Object
  // Signal to show properties dialog
  app.setConfigShowMode(ConfigShowMode.AlwaysShow);
  app.start(); // Start the program
 }
 protected void simpleInitGame() {
  // Make a box
  Box b = new Box("Mybox", new Vector3f(0,0,0), new Vector3f(1,1,1));
  rootNode.attachChild(b); // Put it in the scene graph
 }
}