@SuppressWarnings("unchecked")
  private static <T, U, V, W> InputFormat<T, U> castInputFormat(InputFormat<V, W> from) {
    // This is ugly in two ways...
    // 1) We assume that LlapWrappableInputFormatInterface has NullWritable as first parameter.
    //    Since we are using Java and not, say, a programming language, there's no way to check.
    // 2) We ignore the fact that 2nd arg is completely incompatible (VRB -> Writable), because
    //    vectorization currently works by magic, getting VRB from IF with non-VRB value param.
    // So we just cast blindly and hope for the best (which is obviously what happens).
    return (InputFormat<T, U>)from;
  }
The position of the first byte in the file to process.
ql/src/java/org/apache/hadoop/hive/ql/io/HiveInputFormat.java