public class Javaexcercise {
 
 public static void main(String[] args) {
 
   int num1, num2, temp;
   num1 = 30;
   num2 = 50;
   System.out.println("Before swapping : num1, num2 = "+num1+", "+ + num2);
   temp = num1;
   num1 = num2;
   num2 = temp;   
  System.out.println("After swapping : num1, num2 = "+num1+", "+ + num2);
 }
 }

Result