get.java

public V get(Object key) {
		Entry<K, V> entry = getEntry(key);
		return (entry == null ? null : entry.value);
	}

	private Entry<K, V> getEntry(Object key) {
		if (comparator != null) {
			return getEntryUsingComparator(key);
		}
		if (key == null) {
			throw new NullPointerException();
		}
		Comparable<? super K> searchingKey = (Comparable<? super K>) key;
		Entry<K, V> entry = root;
		while (entry != null) {
			int result = searchingKey.compareTo(entry.key);
			if (result < 0) {
				entry = entry.left;
			} else if (result > 0) {
				entry = entry.right;
			} else {
				return entry;
			}
		}
		return null;
	}

	private Entry<K, V> getEntryUsingComparator(Object key) {
		Comparator<? super K> cpr = comparator;
		if (cpr != null) {
			Entry<K, V> entry = root;
			while (entry != null) {
				int result = cpr.compare((K)key, entry.key);
				if (result < 0) {
					entry = entry.left;
				} else if (result > 0) {
					entry = entry.right;
				} else {
					return entry;
				}
			}
		}
		return null;
	}