Implementation of Queue using Stacks

Queue.java

import java.util.Stack;

public class Queue {

    private Stack s1;
    private Stack s2;

    public Queue() {
        this.s1 = new Stack<Integer>();
        this.s2 = new Stack<Integer>();
    }

    public void enqueue(int data){
        s1.push(data);
    }
    public void dequeue(){
        if(!s2.isEmpty()){
            //pop from stack s2
            System.out.println(s2.pop()+" is dequeued");
        }
        else{
            //pop each item from stack s1 and push into stack s2
            while(!s1.isEmpty()){
                s2.push(s1.pop());
            }
            //Now stack s1 is empty
            //finally, pop from stack s2
            System.out.println(s2.pop()+" is dequeued");
        }
    }
}

Test.java

public class Test {
    public static void main(String[] args) {
        Queue q = new Queue();
        q.enqueue(10);
        q.enqueue(20);
        q.dequeue();
        q.enqueue(30);
        q.dequeue();
        q.enqueue(40);
        q.enqueue(50);
        q.dequeue();
    }
}