public class StackQueue {
 public static void main(String[] args) {
 Stack<String> stack = new Stack<>();
 Queue<String> queue = new Queue<>();

 stack.push("stack-first");
 stack.push("stack-last");

 queue.enqueue("queue-first");
 queue.enqueue("queue-last");

 for (String s : stack) 
 System.out.println("stack contains " + s);
 for (String s : queue)
 System.out.println("queue contains " + s);

 while (!stack.isEmpty())
 System.out.println(stack.pop());
 while (!queue.isEmpty())
 System.out.println(queue.dequeue());
 }
}