code: protected Thread createSystemInPump(InputStream is, OutputStream os) {
      inputStreamPumper = new InputStreamPumper(is, os);
      return newThread(inputStreamPumper);
    }
docs: Creates a stream pumper to copy the given input stream to the given
  output stream.
  
  @param is the System.in input stream to copy from
  @param os the output stream to copy into
  @return the stream pumper thread