/**
     * Ensures capacity when the size exceeds the threshold.
     */
    protected void ensureCapacity() {
        if (size >= threshold) {
            final Entry<K, V>[] oldTable = listTable;
            final int newCapacity = oldTable.length * 2 + 1;
            @SuppressWarnings("unchecked")
            final Entry<K, V>[] newMapTable = new Entry[newCapacity];
            @SuppressWarnings("unchecked")

      } finally {
        unlock();
      }
    }

    /** Expands the table if possible. */
    @GuardedBy("this")
    void expand() {
      AtomicReferenceArray<E> oldTable = table;
      int oldCapacity = oldTable.length();
      if (oldCapacity >= MAXIMUM_CAPACITY) {
        return;
      }

      /*

      } finally {
        unlock();
      }
    }

    /** Expands the table if possible. */
    @GuardedBy("this")
    void expand() {
      AtomicReferenceArray<E> oldTable = table;
      int oldCapacity = oldTable.length();
      if (oldCapacity >= MAXIMUM_CAPACITY) {
        return;
      }

      /*

        postWriteCleanup();
      }
    }

    /** Expands the table if possible. */
    @GuardedBy("this")
    void expand() {
      AtomicReferenceArray<ReferenceEntry<K, V>> oldTable = table;
      int oldCapacity = oldTable.length();
      if (oldCapacity >= MAXIMUM_CAPACITY) {
        return;
      }

      /*

        postWriteCleanup();
      }
    }

    /** Expands the table if possible. */
    @GuardedBy("this")
    void expand() {
      AtomicReferenceArray<ReferenceEntry<K, V>> oldTable = table;
      int oldCapacity = oldTable.length();
      if (oldCapacity >= MAXIMUM_CAPACITY) {
        return;
      }

      /*