code: public void setDefaultNamedOutput(Schema outputSchema) throws TupleMRException {
    	Output output = new Output(true, "DEFAULT", new TupleOutputFormat(outputSchema),
          ITuple.class, NullWritable.class, null);
      namedOutputs.add(output);
    }
docs: Sets the default named output (Tuple format) specs. By using this method one can use an arbitrary number of named outputs
  without pre-defining them beforehand.