@Override
  void addToFreeList(V value) {
    OOMSoftReference<V> ref = mSpareReferences.poll();
    if (ref == null) {
      ref = new OOMSoftReference<>();
    }
    ref.set(value);
    mFreeList.add(ref);
  }
A Bucket that uses OOMSoftReferences to store its free list.
imagepipeline/src/main/java/com/facebook/imagepipeline/memory/OOMSoftReferenceBucket.java