所以我的程序中有一行代码确实不起作用。在游戏课里面。在main方法中调用game类。
问题就出在代码的底部。g、 setcolor（颜色：黑色）；有时不起作用。有时它的工作如预期，我会再次运行它，它不会。

import java.awt.Canvas;  
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;

public class Game extends Canvas implements Runnable {

    private static final long serialVersionUID = 1088212668520606240L;
    public static final int WIDTH = 640, HEIGHT = WIDTH / 12 * 9;
    private Thread thread;
    private boolean running = false;
    private Handler handler;

    public Game() {
        handler = new Handler();
        this.addKeyListener(new KeyInput(handler));
        handler.addObject(new Player(WIDTH/2-32, HEIGHT/2-32, ID.Player)); 
        handler.addObject(new Player(WIDTH/2+64, HEIGHT/2-32, ID.Player2)); 
        new Window(WIDTH, HEIGHT, "Ino", this);

    }

    public synchronized void start() {
        thread = new Thread(this);
        thread.start();
        running = true;
        this.render();
}

    public synchronized void stop() {
        try {
            thread.join();
            running = false;
        }
        catch(Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void run() {
        long lastTime = System.nanoTime();
        double amountOfTicks = 60.0;
        double ns = 1000000000 / amountOfTicks;
        double delta = 0;
        long timer = System.currentTimeMillis();
        int frames = 0;
        while(running) {
            long now = System.nanoTime();
            delta += (now - lastTime) / ns;
            lastTime = now;
            while(delta >= 1) {
                tick();
                delta--;
        }
        if(running)
        render();
        frames++;

        if(System.currentTimeMillis() - timer > 1000) {
            timer += 1000;
            System.out.println("FPS; " + frames);
            frames = 0;
                }
            }
        stop();

        }

    private void tick() {
        handler.tick();
    }

    private void render() {
        BufferStrategy bs = this.getBufferStrategy();
        if(bs == null) {
            return;
        }

        Graphics g = bs.getDrawGraphics();
        g.setColor(Color.black);g.fillRect(0, 0, WIDTH, HEIGHT);

        handler.render(g);

        g.dispose();
        bs.show();

     }

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

看起来很随意。它会像预期的那样连续工作几次，然后甚至在不更改代码的情况下也不会工作。有人知道密码有什么问题吗。处理程序对象不会像图形g那样出现。它甚至不显示错误。只是有时候根本就不会出现。