code: public static <K extends WritableComparable, V extends Writable>
    Writable getEntry(MapFile.Reader[] readers,
                                    Partitioner<K, V> partitioner,
                                    K key,
                                    V value) throws IOException {
      int part = partitioner.getPartition(key, value, readers.length);
      return readers[part].get(key, value);
    }
docs: Get an entry from output generated by this class.