### Question:
LongFloatMap implements Serializable, Cloneable { public void remove(long key) { if (key == KEY_NULL || key == REMOVED) { return; } int index = find(key); if (keys[index] != KEY_NULL) { keys[index] = REMOVED; numEntries--; values[index] = VALUE_NULL; } } LongFloatMap();  LongFloatMap(int initialCapacity); float get(long key); void increment(long key, float delta); int size(); boolean isEmpty(); boolean containsKey(long key); void put(long key, float value); void remove(long key); void clear(); LongPrimitiveIterator keySetIterator(); Set<MapEntry> entrySet(); void rehash(); @Override LongFloatMap clone(); @Override String toString(); @Override int hashCode(); @Override boolean equals(Object other);  }### Answer:
@Test public void testRemove() { LongFloatMap map = new LongFloatMap(); map.put(500000L, 2.0f); map.remove(500000L); assertEquals(0, map.size()); assertTrue(map.isEmpty()); assertNaN(map.get(500000L)); }