Part I:

Create an implementation of a stack for the following interface:

/**

* A stack of items.

*/

public interface ItemStack {

/**

* Push an item onto the stack

*

* @param item item to be pushed

*/

public void pushItem(E item);

/**

* Pop an item of the stack

*

* @return the popped item

* @throw NoSuchElementException if stack is empty

*/

public E popItem();

/**

* Return the item on the top of the stack without removing it

*

* @return the item on the top of the stack

* @throw NoSuchElementException if stack is empty

*/

public E peekItem();

/**

* Test if the stack is empty

*

* @return true if the stack is empty, otherwise false

*/

public boolean isEmpty();

/**

* Clear the stack, removes all items.

*/

public void clear();

}

Part II:

Write JUnit test program to thoroughly test all of the methods of your ItemStack class. Once you are confident is it working correctly, proceed to part III.

need help asap