docs: public void init() {
          frame =  new JFrame("Drools Example");
          frame.setDefaultCloseOperation(conf.isExitOnClose() ? JFrame.EXIT_ON_CLOSE : JFrame.DISPOSE_ON_CLOSE);
          frame.setResizable( false );
          frame.setBackground(Color.BLACK);
          frame.getContentPane().setBackground(Color.BLACK);
  
  
          panel = (JPanel) frame.getContentPane();
          panel.setPreferredSize(new Dimension(conf.getWindowWidth(), conf.getWindowHeight()));
          panel.setLayout(null);
  
          setBounds(0, 0, conf.getWindowWidth(), conf.getWindowHeight());
          panel.add(this);
          setIgnoreRepaint(true);
  
          panel.setFocusable(false); // GameUI is used in Canvas-based games only (Invaders, Pong) and only need keylistener on the external Swing JFrame 
          setFocusable(false);
          KeyListener klistener = new GameKeyListener( ksession.getEntryPoint( "KeyPressedStream" ), ksession.getEntryPoint( "KeyReleasedStream" ) );
          frame.addKeyListener(klistener);
  
          frame.setLocationRelativeTo(null); // Center in screen
          frame.pack();
          frame.setResizable(false);
          frame.setVisible( true );
  
          createBufferStrategy(2);
          bufferStrategy = getBufferStrategy();
      }