public class Test6 {
    
    public static void change(Student s){
        s.setName("B");
    }
    
    public static void change(int i){
        i=2;
    }
    
    public static void main(String[] args) {
        Student s=new Student("A");//创建名叫A的学生
        change(s);//换个名字
        System.out.println(s.getName());//输出名字
        int i=1;
        change(i);//换个i试试
        System.out.println(i);
    }
    
    static class Student{
        private String name;

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

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }
        
    }
}

试试就知道两者的区别了

public class Test6 {   
    public static void change(Student s){
        s.setName("B");
    }
    public static int change(int j){
        j=2000;
    return j;
    }
        public static void main(String[] args) {
        Student stu=new Student("A");//创建名叫A的学生
        change(stu);//换个名字
        System.out.println(stu.getName());//输出名字
        int i=2;
        change(i);//换个i试试
        System.out.println(i);
    }   
    static class Student{
        private String name;
        public Student(String name) {
            this.name=name;
        }
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }        
    }
}
我改成这样，还是不能返回i值。