Java Program to swap two numbers without using temporary variable

import java.util.*;
import java.lang.*;
import java.io.*;

public class SwapNumbers {

    public static void main(String[] args) {

        int first = 6, second = 2;

        System.out.println("--Before swap--");
        System.out.println("First number = " + first);
        System.out.println("Second number = " + second);

        first = first - second;
        second = first + second;
        first = second - first;

        System.out.println("--After swap--");
        System.out.println("First number = " + first);
        System.out.println("Second number = " + second);
    }
}