public void start() throws JSchException{
    Session _session=getSession();
    try{
      sendRequests();
      Request request=new RequestExec(command);
      request.request(_session, this);
    }
    catch(Exception e){
      if(e instanceof JSchException) throw (JSchException)e;
      if(e instanceof Throwable)
        throw new JSchException("ChannelExec", (Throwable)e);
      throw new JSchException("ChannelExec");
    }

    if(io.in!=null){
      thread=new Thread(this);
      thread.setName("Exec thread "+_session.getHost());
      if(_session.daemon_thread){
        thread.setDaemon(_session.daemon_thread);
      }
      thread.start();
    }
  }