Question

我用Eclipse做J2ME 为什么窗口一弹出就消失

Running with storage root DefaultColorPhone
Running with locale: Chinese_People's Republic of China.936
java.lang.NullPointerException
at java.util.Timer.sched(+77)
at java.util.Timer.scheduleAtFixedRate(+45)
at com.myj2me.GaugeTest.<init>(+79)
at java.lang.Class.runCustomCode(+0)
at com.sun.midp.midlet.MIDletState.createMIDlet(+34)
at com.sun.midp.midlet.Scheduler.schedule(+52)
at com.sun.midp.main.Main.runLocalClass(+28)
at com.sun.midp.main.Main.main(+116)
Execution completed.
3476478 bytecodes executed
20 thread switches
1647 classes in the system (including system classes)
18173 dynamic objects allocated (539508 bytes)
2 garbage collections (465068 bytes collected)

Answer 1

很显然是抛出了空指针异常啊。就是你所指的操作的对象为空，会抛出空指针的原因很可能是你的对象没有初始化，即并未分配内存。解决方案：找到那个对象，并实例化。搞定！！

Answer 2

检查这个类GaugeTest的构造函数 问题在这个函数中发生

Answer 3

空指针了