private void rangeCheck(final int index) {
		if (index >= _size)
			throw new IndexOutOfBoundsException(format(
				"Index: %d, Size: %d", index, _size
			));
	}
Return the current elements as an int array.

@return the current elements as an int array
jenetics.ext/src/main/java/io/jenetics/ext/internal/util/IntList.java