import java.util.Deque;
import java.util.LinkedList;

/*
 *  Example of removeFirst() and pollFirst() methods.
 */
public class DequeExample
{

    public static void main( String[] args )
    {
        Deque<Integer> deque = new LinkedList<Integer>();
        deque.add(100);
        deque.add(200);
        deque.add(300);

        System.out.println("deque : " + deque + "\n");

        /*
         * Retrieves and removes the first element of this deque. This method
         * differs from pollFirst only in that it throws an exception if this
         * deque is empty.
         */
        Integer removedElement = deque.removeFirst();

        System.out.println("removedElement : " + removedElement);
        System.out.println("deque : " + deque + "\n");

        /*
         * Retrieves and removes the first element of this deque, or returns
         * null if this deque is empty.
         */
        removedElement = deque.pollFirst();
        System.out.println("removedElement : " + removedElement);
        System.out.println("deque : " + deque + "\n");

    }
}