getOfferedOverlapItem

       /**
	 * Returns a GameItem object if any of the items offered by the player exist in the
	 * recipients inventory, and if the combined total amount is greater than the maximum
	 * value of an Integer type.
	 * @param player the player with the offered items were checking
	 * @return a GameItem object if the pre-explained conditions are met
	 */
	private GameItem getOfferOverlapItem(Client player) {
		Client recipient = getOther(player);
		for (GameItem playerItem : items.get(player)) {
			if (!playerItem.isStackable()) {
				continue;
			}
			if (!recipient.getItems().playerHasItem(playerItem.getId())) {
				continue;
			}
			long amount = ((long) playerItem.getAmount()
					+ (long) recipient.getItems().getItemAmount(playerItem.getId()));
			if (amount > Integer.MAX_VALUE) {
				return new GameItem(playerItem.getId(), recipient.getItems().getItemAmount(playerItem.getId()));
			}
		}
		return null;
	}