1 public class Test extends MIDlet
 2 {
 3     private Display display;
 4 
 5     public Test() {
 6         display = Display.getDisplay(this);
 7     }
 8     public void startApp() {
 9         display1 d = new display1();
10         display.setCurrent(d);
11         d.a();
12     }
13     public void pauseApp() {
14     }
15     public void destroyApp(boolean unconditional){
16     }
17      
18 }
19  class display1 extends Canvas {
20     private Graphics g1;
21     private Font f = Font.getFont(0, 1, 16);
22     
23     public display1()
24     {
25     }
26 
27     public final void a()
28     {
29         repaint();
30         serviceRepaints();
31         g1.setFont(f);
32     }
33 
34     public final void paint(Graphics g)
35     {
36         if (g1 == null)
37         {
38             g1 = g;
39         }
40         //To do
41     }
42 }
43 
正常的情况应该是setCurrent后执行paint()，对g1初始化，但在我的环境下跑却是直接执行a()，而g1还没初始化，出现空指针异常，请教高手大侠们，有研究过setCurrent的实现机制吗？问题很急，万分感谢ing