public class ArrayQueue<E> implements QueueInterface<E> {

   private int front = -1;
   private int rear = -1;
   private E[] array;
   private int manyItems;

   public void enqueue(E e) {
      if (rear == -1) {
         front = rear = e; // **this line gives an incompatible type error**
      } // end if

      if (rear + 1 > (array.length - 1) ) {
         E[] temp;
         temp = (E[]) new Object[array.length * 2];
         for (int i = 0; i < array.length; i++) {
            temp[i] = array[i];
         } // end for loop
         array = temp;
         array[rear + 1] = e;
         rear = rear + 1;
      } // end if

      else {
         array[rear + 1] = e;
         rear = rear + 1;
      } // end else

   } // end enqueue method

   public E dequeue() {
      if (front == -1) {
         throw new IllegalStateException("The queue is empty, cannot dequeue");
      } // end if

      E e = front; // **this line gives an incompatible type error**
      front = front + 1;

      return e;

   } // end dequeue method

   public E front() {
      if (front == -1) {
         throw new IllegalStateException("The queue is empty, cannot return front");
      } // end if

      E e = front; // **this line gives an incompatible type error**

      return e;

   } // end front method

} // end ArrayQueue class

E e = front;