Swap.java

public class Swap {
    // swap method for int
    public static void swap(int i, int j){
        int temp = i;
        i = j;
        j = temp;
        System.out.println("swap内（int）：x=" + i + ", y=" + j);
    }
    // swap method for Integer
    public static void swap(Integer i, Integer j){
        Integer temp = i;
        i = j;
        j = temp;
        System.out.println("swap内（integer）：x=" + i + ", y=" + j);
    }   
    // main method
    public static void main(String[] args){
        // test swap with int 
        int a = 10;
        int b = 20;
        System.out.println("swap.int:");
        System.out.println("Before swap: a = " + a + ", b = " + b);
        swap(a, b);
        System.out.println("After swap: a = " + a + ", b = " + b);
// test swap with Integer
      // 方法1：自动装箱（最简洁，推荐）
        Integer x = 100;
        Integer y = 200;
        System.out.println("swap.Integer:");
        System.out.println("Before swap: x = " + x + ", y = " + y);
        swap(x, y);
        System.out.println("After swap: x = " + x + ", y = " + y);
    }
}