class pc1{                           //画一个矩形
    public pc1(Color c,int x,int y){
        this.c=c;this.x=x;this.y=y;
    }
    Color c;int x,y;
    public void draw(Graphics g){
        g.setColor(c);
        g.fillRect(x, y, 50, 50);
    }
}

class Producer extends Thread{          //线程
    public Producer(Graphics2D g1){
        this.g=g1;
    }
    pc1 pct=new pc1(Color.BLUE,50,50);
    Graphics2D g;
    public void run(){
        while(true){         
            try {
                pct.draw(g);            //调用pctr的draw()方法
                Thread.sleep(5000);
       }
       catch (Exception ex) {}
        }
    }
}

class contentpanel extends JPanel{
    Graphics2D g2;
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        g2=(Graphics2D)g;
        pt.draw(g);
        c1.start();p1.start();
    }
    pc1 pt=new pc1(Color.BLUE,50,50);
    Producer p1=new Producer(g2);
    Cus c1=new Cus(g2);
}
---------------------------------------------
以上是一部分代码。为啥我直接调用方法以就行了..但是用个线程转了下就不行了..麻烦高手指教下
顺便问下怎么用 图形界面模拟生产消费者的问题