异常处理 1.04

1. 是程序中的不正常事件，不包括语法错误和逻辑错误
2. Error(错误)：Java虚拟机不能解决严重问题
3. Exception(异常)：外在因素或编译错误一般性问题
4. 异常分运行时异常(可以不处理)和编译时异常(必须处理)

public class Exception00 {
    public static void main(String[] args) {
        //no1
        Integer[] integers = new Integer[3];
        integers[4] = 4;
        //no2
        System.out.println(1 / 0);
        //no3
            A b =   new B();
            B b2 = (B)b;
            C c = (C)b;
        //no4
        String a = null;
        System.out.println(a.length());
        //no5
        String  name = "smith";
        int i = Integer.parseInt(name);
        System.out.println(i);

    }
}
class A{}
class B extends A{}
class C extends A{}

throws

try - catch (ctrl + alt + j)

public class Throws_ {
    public static void main(String[] args) throws Exception{
        try {
            System.out.println(1 / 0);
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            System.out.println("!!!");
        }
    }
}

        System.out.println("!!!");
    }
}

}