code: public static void setQueries(List<String> queries, Configuration conf) throws IOException {
      Preconditions.checkNotNull(queries);
      Preconditions.checkArgument(!queries.isEmpty());
      HadoopUtils.writeStringListToConfAsBase64(QUERIES_KEY, queries, conf);
    }
docs: Set the queries to run over the indexes
  These can be Strings suitable for parsing with a QueryParser, or they can be
  a custom serialized Query object. They have to be Strings so that they can be
  written to the job conf. They will be deserialized / parsed by the abstract
  method {@link LuceneIndexRecordReader#deserializeQuery(String)}
  
  @param queries queries to run over the indexes
  @param conf job conf
  @throws IOException