Swapping two numbers without using a new variable is always a good approach. This helps your application to be memory and performance oriented.

public class Swap2Numbers{   int firstNum = 10;   int secondNum = 20;      public static void main(String args[])   {      Swap2Numbers swap2Numbers = new Swap2Numbers();      swap2Numbers.proceed();   }      private void proceed()   {      System.out.println("Before swapping... ");      System.out.println("firstNum: " + firstNum);      System.out.println("secondNum: " + secondNum);            firstNum = firstNum + secondNum;      secondNum = firstNum - secondNum;      firstNum = firstNum - secondNum;      System.out.println("
After swapping... ");      System.out.println("firstNum: " + firstNum);      System.out.println("secondNum: " + secondNum);         }}/*

Expected output:

[root@mypc]# java Swap2NumbersBefore swapping...firstNum: 10secondNum: 20After swapping...firstNum: 20secondNum: 10*/