jodd-core/src/main/java/jodd/util/collection/IntHashMap.java
public Object put(final int key, final Object value) {
		// makes sure the key is not already in the IntHashMap.
		Entry[] tab = table;

		int index = (key & 0x7FFFFFFF) % tab.length;
		for (Entry e = tab[index]; e != null; e = e.next) {
			if (e.key == key) {
				Object old = e.value;
				e.value = value;
				return old;
			}
		}

		modCount++;
		if (count >= threshold) {
			// rehash the table if the threshold is exceeded
			rehash();

			tab = table;
			index = (key & 0x7FFFFFFF) % tab.length;
		}

		// creates the new entry.
		tab[index] = new Entry(key, value, tab[index]);
		count++;
		return null;
	}
public Object put(final int key, final Object value) {
		// makes sure the key is not already in the IntHashMap.
		Entry[] tab = table;

		int index = (key & 0x7FFFFFFF) % tab.length;
		for (Entry e = tab[index]; e != null; e = e.next) {
			if (e.key == key) {
				Object old = e.value;
				e.value = value;
				return old;
			}
		}

		modCount++;
		if (count >= threshold) {
			// rehash the table if the threshold is exceeded
			rehash();

			tab = table;
			index = (key & 0x7FFFFFFF) % tab.length;
		}

		// creates the new entry.
		tab[index] = new Entry(key, value, tab[index]);
		count++;
		return null;
	}
Associates the specified value with the specified key in this map. If the
map previously contained a mapping for this key, the old value is
replaced.

@param key key with which the specified value is to be associated.
@param value value to be associated with the specified key.
@return previous value associated with specified key, or <code>null</code> if
there was no mapping for key. A <code>null</code> return can also indicate
that the IntHashMap previously associated <code>null</code> with the
specified key.