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

/*
 *  Example of size() method.
 */
public class DequeExample
{

    public static void main(String[] args)
    {
        Deque<Integer> deque = new LinkedList<Integer>();
        deque.add(2000);
        deque.add(5000);
        deque.add(10000);

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

        /*
         * Returns the number of elements in this deque.
         */
        int size = deque.size();
        System.out.println("size : " + size);

    }

}

Output