code: private void setProcessInputStream(OutputStream os) {
          if (input != null) {
              inputThread = createPump(input, os, true);
          } else {
              AntFileUtils.close(os);
          }
      }
docs: Set the <code>OutputStream</code> by means of which
  input can be sent to the process.
  @param os the <code>OutputStream</code>.