instanceof 作用

// obj instanceof class   ;左边是否为实例或存在继承 实现接口的关系 
//符合返回 true 
   public static void main(String[] args) {
        try {
            int[] ints = {1,2,3};
            System.out.println(ints[3]);

        }catch (Exception e ){
            System.out.println(e);
            Throwable cause = e.getCause();
            System.out.println(cause);
            if (e instanceof NullPointerException) {
                System.out.println("补货空指针异常");
            }
            else if(e instanceof ArrayIndexOutOfBoundsException){
                System.out.println("补货数据下边越界异常");

            }
        }
    }