Niu Ke (5) Two stacks to implement a queue

// Implement a queue with two stacks to complete the Push and Pop operations of the queue. The elements in the queue are of type int. 

    Stack<Integer> stack1 = new Stack<Integer>(); 
    Stack<Integer> stack2 = new Stack<Integer>(); 

    public void push(int node) { 
        stack1.push(node); 
    } 

    public int pop() { 
        if (stack2.isEmpty()){ 
            while (!stack1.isEmpty()){ 
                stack2.push(stack1.pop()); 
            } 
        } 
        return stack2.pop(); 
    }