code: private boolean bucketsEmpty() {
          for (int i = 0; i < numberOfBuckets; i++) {
              if (bucketContainer.getBucket(i).elementsInBucket > 0) {
                  return false;
              }
          }
          return true;
      }
docs: checks, if the buckets are empty. Returns true only if all buckets are empty.
  
  @return true only if all buckets are empty