@Override
  public boolean doNext(K key, V value) throws IOException {
    while ((recordReader == null) || !doNextWithExceptionHandler(key, value)) {
      if (!initNextRecordReader()) {
        return false;
      }
    }
    return true;
  }
BucketizedHiveRecordReader is a wrapper on a list of RecordReader. It behaves
similar as HiveRecordReader while it wraps a list of RecordReader from one
file.
ql/src/java/org/apache/hadoop/hive/ql/io/BucketizedHiveRecordReader.java