/**

     * The array buffer into which the elements of the ArrayList are stored.

     * The capacity of the ArrayList is the length of this array buffer. Any

     * empty ArrayList with elementData == EMPTY_ELEMENTDATA will be expanded to

     * DEFAULT_CAPACITY when the first element is added.

     */

    private transient Object[] elementData;

    /**

     * Shared empty array instance used for empty instances.

     */

    private static final Object[] EMPTY_ELEMENTDATA = {};

    /**

     * Constructs an empty list with an initial capacity of ten.

     */

    public ArrayList() {

        super();

        this.elementData = EMPTY_ELEMENTDATA;

    }

    /**

     * Appends the specified element to the end of this list.

     *

     * @param e element to be appended to this list

     * @return <tt>true</tt> (as specified by {@link Collection#add})

     */

    public boolean add(E e) {

        ensureCapacityInternal(size + 1);  // Increments modCount!!

        elementData[size++] = e;

        return true;

    }

    private void ensureCapacityInternal(int minCapacity) {

        if (elementData == EMPTY_ELEMENTDATA) {

            minCapacity = Math.max(DEFAULT_CAPACITY, minCapacity);

        }

        ensureExplicitCapacity(minCapacity);

    }

    private void ensureExplicitCapacity(int minCapacity) {

        modCount++;

        // overflow-conscious code

        if (minCapacity - elementData.length > 0)

            grow(minCapacity);

    }

    /**

     * Increases the capacity to ensure that it can hold at least the

     * number of elements specified by the minimum capacity argument.

     *

     * @param minCapacity the desired minimum capacity

     */

    private void grow(int minCapacity) {

        // overflow-conscious code

        int oldCapacity = elementData.length;

        int newCapacity = oldCapacity + (oldCapacity >> 1);

        if (newCapacity - minCapacity < 0)

            newCapacity = minCapacity;

        if (newCapacity - MAX_ARRAY_SIZE > 0)

            newCapacity = hugeCapacity(minCapacity);

        // minCapacity is usually close to size, so this is a win:

        elementData = Arrays.copyOf(elementData, newCapacity);

    }

    /**

     * Returns the element at the specified position in this list.

     *

     * @param  index index of the element to return

     * @return the element at the specified position in this list

     * @throws IndexOutOfBoundsException {@inheritDoc}

     */

    public E get(int index) {

        rangeCheck(index);

        return elementData(index);

    }

    @SuppressWarnings("unchecked")

    E elementData(int index) {

        return (E) elementData[index];

    }