code: private void start()
      {
      try
        {
        // Initialize filter.
        initializeFilter( getFilterInput(), getFilterOutput());
  
        // Start filter thread.
        failure_ = null;
        thread_ = new Thread( this, String.valueOf( this));
        thread_.start();
        }
      catch( Exception e)
        {
        throw new RuntimeException( "Can't start filtering", e);
        } 
      }
docs: Starts filter output.