code: void resizeEntries(int newCapacity) {
      this.elements = Arrays.copyOf(elements, newCapacity);
      long[] entries = this.entries;
      int oldCapacity = entries.length;
      entries = Arrays.copyOf(entries, newCapacity);
      if (newCapacity > oldCapacity) {
        Arrays.fill(entries, oldCapacity, newCapacity, UNSET);
      }
      this.entries = entries;
    }
docs: Resizes the internal entries array to the specified capacity, which may be greater or less than
  the current capacity.