exercises

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遇到的题目

2019.08.05

静态分布

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public class TestXu {

    public static void say(Object arg){
        System.out.println("Object");
    }
    public static void say(int arg){
        System.out.println("int");
    }
    public static void say(long arg){
        System.out.println("long");
    }
    public static void say(char arg){
        System.out.println("char");
    }
    public static void say(Character arg){
        System.out.println("character");
    }
    
    public static void main(String[] args){
        say('a');
    }
}

打印结果为:char

如果注释掉形参为char的重载函数,接下来会打印int,反复执行,打印的顺序应该为:

char->int->long->Character->Object

因为,如果形参为char的重载函数被注释,实参’a’会向上转化成65,接下来,它转换成long,float,double,如果都没有找到,那么他会自动装箱成Character类型,接下来它会找到所继承的接口,最后找到万能类Object,由此可见,变长参数的优先级是最低的.

2019.08.06

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public class Main {
       static int a;
       public static void main(String[] args){
           int b;
           System.out.println(a);//这句不会报错
           System.out.println(b);//这句会报错
       }
    }