@J2ktIncompatible
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
    stream.defaultReadObject();
    int distinctElements = Serialization.readCount(stream);
    setBackingMap(Maps.<E, Count>newHashMap());
    Serialization.populateMultiset(this, stream, distinctElements);
  }

  @GwtIncompatible // Not needed in emulated source.
  @J2ktIncompatible

    checkArgument(backingMap.isEmpty());
    this.backingMap = backingMap;
  }

  /** Used during deserialization only. The backing map must be empty. */
  void setBackingMap(Map<E, Count> backingMap) {
    this.backingMap = backingMap;
  }

  // Required Implementations

  /**
   * {@inheritDoc}
   *