问GLCanvas和JFrame如何协同工作？

EN

public class OpenGL extends JFrame implements GLEventListener {

    GLCanvas glCanvas;

    public OpenGL() {
        setTitle("First OpenGL Program");
        setSize(600, 600);
        setLocation(0, 0);
        glCanvas = new GLCanvas();
        glCanvas.addGLEventListener(this);
        this.add(glCanvas);
        setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public static void main (String[] args) {
        new OpenGL();
    }
}

glCanvas.addGLEventListener(this);
this.add(glCanvas);