I tried in ClientToProxyIoHandler :

   @Override
    public void messageSent(IoSession session, Object Message) throws Exception {
        NcarLogger.development.debug("Message sent to client " + session.getId());

        // lets close the proxy connection between mina and jetty
		IoSession remote = (IoSession) session.getAttribute("REMOTE");
//		if (remote != null) {
//			int count = 1;
//			while(!remote.isBothIdle() && count <= 60) {
//				System.out.println("remote session " + remote.getId() + " is not idle yet" + count + ". Waiting ...");
//				Thread.sleep(1000);
//
//				count ++;
//			}
//			System.out.println("remote session " + remote.getId() + " is idle. Closing ...");
//			remote.close(false);
//		} else {
//           System.out.print("remote session was null");
//		}
    }