SOURCE CODE: 

import java.util.*;
 
class SwapTwoNumbersFunc
{
    int a,b;
   
    public  void swap(SwapTwoNumbersFunc swp)
    {
        int temp;
        temp=swp.a;
        swp.a=swp.b;
        swp.b=temp;
    }
    public static void main(String s[])
    {
        SwapTwoNumbersFunc objSwp= new SwapTwoNumbersFunc();
        try
        {
            Scanner sc=new Scanner(System.in);
             
            System.out.print("Enter first  number: ");
            objSwp.a=sc.nextInt();
             
            System.out.print("Enter second number: ");
            objSwp.b=sc.nextInt();
             
            objSwp.swap(objSwp);
            System.out.println("After swapping  -a: " + objSwp.a + ", b: " + objSwp.b);
        }
        catch(Exception E)
        {
            System.out.println("Exception: " + E.toString());
        }
    }
}

OUTPUT ::

Enter first  number: 1
    Enter second number: 2
    After swapping  a: 2, b: 1