Java day08 异常（2）

class NegativeException extends ArithmeticException {NegativeException(String msg){super(msg);}}//若在方法体中抛出非RuntimeException,而在方法上没有声明该异常，则发生编译错误class Div{int div(int a,int b){if(b<0)throw new NegativeException("除数是负数");else if(b==0)throw new RuntimeException("除以了0");elsereturn a/b;}}class RuntimeDemo{public static void main(String[] args) {Div d=new Div();d.div(4,0);}}