Java学习----有风险的代码(异常)

Exception继承了Throwable，但是它本身是有异常类的父类。

RuntimeException：运行时异常

 

Exception->RuntimeException->NullPointException

Exception->RuntimeException->IndexOutOfBoundsException->ArrayIndexOfboundsException

 

public class Test {
    
    String x;
    public static void main(String[] args) {
        
        Test test = new Test();
        try {
            System.out.println(test.x.length());
        } catch (ArrayIndexOutOfBoundsException e) {
            test.x = "hello world";
            System.out.println(test.x.length());
        } catch (NullPointerException e) {
            // TODO: handle exception
            test.x = "hello world";
            System.out.println(test.x.length());
        } catch (Exception e) { // 必须放到最后
            // TODO: handle exception
            e.printStackTrace();
        }
        
        System.out.println("end");
    }
}

 

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