12.7.1 特例:RuntimeException

RuntimeException是一个特例,无需写异常声明, 事实上也无法这么做, 因为runtimeException一般都是一些运行时产生的无法预知的问题.当产生一个RuntimeException并且抛出到最外层的main入口函数时,程序库将结束执行, 并显示调用栈信息.

package com.cnsuning.src;public class Main {public Main() {// TODO Auto-generated constructor stub}public static void main(String[] args) {Main m = new Main();//m.test();m.test1();}public void test(){throw new RuntimeException();}public void test1(){Main m = null;m.test();}}

Exception in thread "main" java.lang.NullPointerExceptionat com.cnsuning.src.Main.test1(Main.java:21)at com.cnsuning.src.Main.main(Main.java:12)