private Context createContext(Configuration conf, int numSplits) throws IOException {
    // Use threads to resolve directories into splits.
    if (HiveConf.getBoolVar(conf, HiveConf.ConfVars.HIVE_ORC_MS_FOOTER_CACHE_ENABLED)) {
      // Create HiveConf once, since this is expensive.
      conf = new HiveConf(conf, OrcInputFormat.class);
    }
    return new Context(conf, numSplits, null);
  }
An InputFormat for ORC files. Keys are meaningless,
value is the OrcStruct object
ql/src/java/org/apache/hadoop/hive/ql/io/orc/OrcNewInputFormat.java