### Question:
ConcurrentLongLongHashMap { public long putIfAbsent(long key, long value) { checkBiggerEqualZero(key); checkBiggerEqualZero(value); long h = hash(key); return getSection(h).put(key, value, (int) h, true, null); } ConcurrentLongLongHashMap();  ConcurrentLongLongHashMap(int expectedItems);  ConcurrentLongLongHashMap(int expectedItems, int concurrencyLevel); long size(); long capacity(); boolean isEmpty(); long get(long key); boolean containsKey(long key); long put(long key, long value); long putIfAbsent(long key, long value); long computeIfAbsent(long key, LongLongFunction provider); long addAndGet(long key, long delta); boolean compareAndSet(long key, long currentValue, long newValue); long remove(long key); boolean remove(long key, long value); int removeIf(LongPredicate filter); int removeIf(LongLongPredicate filter); void clear(); void forEach(BiConsumerLong processor); List<Long> keys(); List<Long> values(); Map<Long, Long> asMap();  }### Answer:
@Test public void testPutIfAbsent() { ConcurrentLongLongHashMap map = new ConcurrentLongLongHashMap(); assertEquals(map.putIfAbsent(1, 11), -1); assertEquals(map.get(1), 11); assertEquals(map.putIfAbsent(1, 111), 11); assertEquals(map.get(1), 11); }