实例化对象疑惑
public class TankClient extends Frame {
public static final int GAME_WIDTH = 800;
public static final int GAME_HEIGHT = 600;

Tank myTank = new Tank(50, 50);

Image offScreenImage = null;

public void paint(Graphics g) {
myTank.draw(g);
}

public void update(Graphics g) {
if(offScreenImage == null) {
offScreenImage = this.createImage(GAME_WIDTH, GAME_HEIGHT);
}
Graphics gOffScreen = offScreenImage.getGraphics();
Color c = gOffScreen.getColor();
gOffScreen.setColor(Color.GREEN);
gOffScreen.fillRect(0, 0, GAME_WIDTH, GAME_HEIGHT);
gOffScreen.setColor(c);
paint(gOffScreen);
g.drawImage(offScreenImage, 0, 0, null);
}

public void lauchFrame() {
this.setLocation(400, 300);
this.setSize(GAME_WIDTH, GAME_HEIGHT);
this.setTitle("TankWar");
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
this.setResizable(false);
this.setBackground(Color.GREEN);

this.addKeyListener(new KeyMonitor());

setVisible(true);

new Thread(new PaintThread()).start();
}

public static void main(String[] args) {
TankClient tc = new TankClient();
tc.lauchFrame();
}

private class PaintThread implements Runnable {

public void run() {
while(true) {
repaint();
try {
Thread.sleep(50);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}

private class KeyMonitor extends KeyAdapter {

public void keyPressed(KeyEvent e) {
myTank.keyPressed(e);
}

}
}
大家帮我看看，实例化TankClient执行的是tc.lauchFrame();没有写tc.paint(g),paint(g)能被执行吗？是不是实例化对象之后，必须tc.a,tc.b......才能执行所有的方法。

------解决方案--------------------
能，paint()方法对于Frame来说，是一个需要重绘时自动调用的方法，相当于回调方法。你看JDK API就明白了。
------解决方案--------------------
lauchFrame中调用了setVisable方法，调用该方法之后就开始绘制组件，绘制组件的时候就会调用
你override的paint、update等方法。