[数据结构与算法]java值传递问题

定义类：

class Student {
    String name;
    int sex;

    public Student(String name, int sex) {
        this.name = name;
        this.sex = sex;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", sex=" + sex +
                '}';
    }
}

public class demo {
    public static void main(String[] args) {
        int a = 123;
        int b = 456;
        hand(a, b);
        System.out.println(a + "  " + b);
        Student s1 = new Student("zhang", 18);
        Student s2 = new Student("li", 20);
        hand(s1, s2);
        System.out.println(s1);
        System.out.println(s2);
        Student s3 = new Student("zhao", 19);
        Student s4 = new Student("zhou", 21);
        hand1(s3, s4);
        System.out.println(s3);
        System.out.println(s4);
    }

    //数值交换——失败
    private static void hand(int a, int b) {
        int t = a;
        a = b;
        b = t;
    }

    //类交换——失败
    private static void hand(Student s1, Student s2) {
        Student s = s1;
        s1 = s2;
        s2 = s;
    }

    //交换成功
    private static void hand1(Student s1, Student s2) {
        Student s = new Student("haha", 9);
        s.name = s1.name;
        s1.name = s2.name;
        s2.name = s.name;
    }
}

?

输出结果：