* successors, see the comments near the end of CompactHashMap, noting that the methods here call
   * requirePredecessors() and requireSuccessors(), which are defined at the end of this file.
   */

  private int getPredecessor(int entry) {
    return requirePredecessors()[entry] - 1;
  }

  @Override
  int getSuccessor(int entry) {
    return requireSuccessors()[entry] - 1;
  }