@Nullable
  public CloseableReference<V> get(final K key) {
    Preconditions.checkNotNull(key);
    Entry<K, V> oldExclusive;
    CloseableReference<V> clientRef = null;
    synchronized (this) {
      oldExclusive = mExclusiveEntries.remove(key);
      Entry<K, V> entry = mCachedEntries.get(key);
      if (entry != null) {
        clientRef = newClientReference(entry);
      }
    }
    maybeNotifyExclusiveEntryRemoval(oldExclusive);
    maybeUpdateCacheParams();
    maybeEvictEntries();
    return clientRef;
  }
Gets the item with the given key, or null if there is no such item.

<p>It is the caller's responsibility to close the returned reference once not needed anymore.
imagepipeline-base/src/main/java/com/facebook/imagepipeline/cache/LruCountingMemoryCache.java