public void trimToSize() {
		if (_size < _data.length) {
			_data = _size == 0
				? EMPTY_ARRAY
				: copyOf(_data, _size);
		}
	}
Trims the capacity of this {@code ArrayList} instance to be the list's
current size.  An application can use this operation to minimize the
storage of an {@code ArrayList} instance.
jenetics.ext/src/main/java/io/jenetics/ext/internal/util/IntList.java