private void rebuild() {
		size = 0;
		MapEntry<K, V> tree[] = new MapEntry[structure.length * 2];
		MapEntry<K, V> old[] = structure;
		structure = tree;

		for (MapEntry<K, V> e : old) {
			if (e != null) {
				put(e.key, e.value);

			}
		}
	}