1  import java.util.Arrays;

  2  

  3  public class Stack<E>

  4  {

  5     private Object[] elements;

  6     private int currentSize;

  7     

  8     private static final int INITIAL_SIZE = 10;

  9  

 10     public Stack()

 11     {

 12        elements = new Object[INITIAL_SIZE]; 

 13        // elements = new E[INITIAL_SIZE] 

 14        // is an error--cannot make a generic array

 15     }

 16  

 17     public void push(E value)

 18     {

 19        if (currentSize >= elements.length) 

 20        {

 21           elements = Arrays.copyOf(elements, 2 * elements.length);

 22        }

 23        elements[currentSize] = value;

 24        currentSize++;

 25     }

 26  

 27     @SuppressWarnings("unchecked") // Suppresses "unchecked" warnings inside this method

 28     public E pop()

 29     {

 30        currentSize--;

 31        return (E) elements[currentSize]; // Cast causes "unchecked" warning

 32     }

 33     

 34     public int size() { return currentSize; }

 35  }