assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));
    assertFalse(segment.containsValue(nullValue));

    // hash collision
    InternalEntry<Object, Object, ?> dummyEntry =
        segment.newEntryForTesting(new Object(), hash, entry);
    Object dummyValue = new Object();
    WeakValueReference<Object, Object, ?> dummyValueRef =

    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));
    assertFalse(segment.containsValue(nullValue));

    // hash collision
    InternalEntry<Object, Object, ?> dummyEntry =
        segment.newEntryForTesting(new Object(), hash, entry);
    Object dummyValue = new Object();
    WeakValueReference<Object, Object, ?> dummyValueRef =

   *
   * Per-thread hash codes are initialized to random values.
   * Contention and/or table collisions are indicated by failed
   * CASes when performing an update operation (see method
   * retryUpdate). Upon a collision, if the table size is less than
   * the capacity, it is doubled in size unless some other thread
   * holds the lock. If a hashed slot is empty, and lock is
   * available, a new Cell is created. Otherwise, if the slot

    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));
    assertFalse(segment.containsValue(nullValue));

    // hash collision
    DummyEntry<Object, Object> dummy = DummyEntry.create(new Object(), hash, entry);
    Object dummyValue = new Object();
    ValueReference<Object, Object> dummyValueRef = map.newValueReference(dummy, dummyValue, 1);

    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));
    assertFalse(segment.containsValue(nullValue));

    // hash collision
    DummyEntry<Object, Object> dummy = DummyEntry.create(new Object(), hash, entry);
    Object dummyValue = new Object();
    ValueReference<Object, Object> dummyValueRef = map.newValueReference(dummy, dummyValue, 1);

   *
   * Per-thread hash codes are initialized to random values.
   * Contention and/or table collisions are indicated by failed
   * CASes when performing an update operation (see method
   * retryUpdate). Upon a collision, if the table size is less than
   * the capacity, it is doubled in size unless some other thread
   * holds the lock. If a hashed slot is empty, and lock is
   * available, a new Cell is created. Otherwise, if the slot

      int leftCode = identityHashCode(left);
      int rightCode = identityHashCode(right);
      if (leftCode != rightCode) {
        return leftCode < rightCode ? -1 : 1;
      }

      // identityHashCode collision (rare, but not as rare as you'd think)
      int result = getUid(left).compareTo(getUid(right));
      if (result == 0) {
        throw new AssertionError(); // extremely, extremely unlikely.
      }

   *
   * Per-thread hash codes are initialized to random values.
   * Contention and/or table collisions are indicated by failed
   * CASes when performing an update operation (see method
   * retryUpdate). Upon a collision, if the table size is less than
   * the capacity, it is doubled in size unless some other thread
   * holds the lock. If a hashed slot is empty, and lock is
   * available, a new Cell is created. Otherwise, if the slot

      SortedMap<K, V> map, Entry<? extends K, ? extends V> entry) {
    K key = checkNotNull(entry.getKey());
    V value = checkNotNull(entry.getValue());
    if (map.containsKey(key)) {
      // When a collision happens, the colliding entry is the first entry
      // of the tail map.
      Entry<K, V> previousEntry = map.tailMap(key).entrySet().iterator().next();
      throw new IllegalArgumentException(