public void stopClients() {
   if (outputClient != null) {
     try {
       outputClient.stop();
     } catch (Exception e) {
     }
   }
   if (inputClient != null) {
     try {
       inputClient.stop();
     } catch (Exception e) {
     }
   }
 }
 public void stopInputClient() throws Exception {
   if (inputClient != null) {
     inputClient.stop();
     inputClient.join();
   }
 }