stream.defaultReadObject();
    int distinctElements = Serialization.readCount(stream);
    backingMap = newBackingMap(ObjectCountHashMap.DEFAULT_SIZE);
    Serialization.populateMultiset(this, stream, distinctElements);
  }

  @GwtIncompatible // Not needed in emulated source.
  @J2ktIncompatible
  private static final long serialVersionUID = 0;

    return oldCount;
  }

  private static int getAndSet(@CheckForNull Count i, int count) {
    if (i == null) {
      return 0;
    }

    return i.getAndSet(count);
  }

  // Don't allow default serialization.
  @GwtIncompatible // java.io.ObjectStreamException
  @J2ktIncompatible
  private void readObjectNoData() throws ObjectStreamException {
    throw new InvalidObjectException("Stream data required");
  }