Java - Swapping values within Object

package passing_32_blog;

public class Pass {

public static void main(String[] args) {
// TODO Auto-generated method stub
First obj1 = new First(10,20);
First obj2 = new First(30,40);
System.out.println("The values before swap are " +obj1.i+"\t" +obj1.j);
obj2.swap(obj1);
System.out.println("The values after swap are " +obj1.i+"\t" +obj1.j);
}
}

package passing_32_blog;

public class First {

int i,j;

First (int k,int l){

i=k;

j=l;

}

void swap(First s){

int temp;

temp = s.i;

s.i=s.j;

s.j=temp;

}

}

Output:-

The values before swap are 10 20

The values after swap are    20 10