public void leaveChat(String address) {
   try {
     udpHandler.leaveGroup(address);
   } catch (IOException e) {
     System.out.println("Client: leaveChat: error in leaving chat = " + address);
     e.printStackTrace();
     // Something goes wrong, break client
     killClient();
   }
 }
 private void killClient() {
   System.out.println("Client: break client");
   tcpHandler.close();
   udpHandler.close();
 }