#fixed code
                                public void shutdown() throws InterruptedException {

        //remove all webServices
        WebService[] services;
        synchronized (this){
            services = new WebService[registeredServices.values().size()];
            registeredServices.values().toArray(services);
        }

        for(WebService service : services){
            removeService(service.getPath());
        }

        //some time to send possible update notifications (404_NOT_FOUND) to observers
        Thread.sleep(1000);

        //Close the datagram datagramChannel (includes unbind)
        ChannelFuture future = channel.close();

        //Await the closure and let the factory release its external resource to finalize the shutdown
        future.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                DatagramChannel closedChannel = (DatagramChannel) future.getChannel();
                log.info("Server channel closed (port {}).", closedChannel.getLocalAddress().getPort());

                channel.getFactory().releaseExternalResources();
                log.info("External resources released, shutdown completed (port {}).",
                        closedChannel.getLocalAddress().getPort());
            }
        });

        future.awaitUninterruptibly();
    }
#vulnerable code 
                                public void shutdown(){

        //remove all webServices
        WebService[] services;
        synchronized (this){
            services = new WebService[registeredServices.values().size()];
            registeredServices.values().toArray(services);
        }

        for(WebService service : services){
            removeService(service.getPath());
        }

        //Close the datagram datagramChannel (includes unbind)
        ChannelFuture future = channel.close();

        //Await the closure and let the factory release its external resource to finalize the shutdown
        future.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                DatagramChannel closedChannel = (DatagramChannel) future.getChannel();
                log.info("Server channel closed (port {}).", closedChannel.getLocalAddress().getPort());

                channel.getFactory().releaseExternalResources();
                log.info("External resources released, shutdown completed (port {}).",
                        closedChannel.getLocalAddress().getPort());
            }
        });

        future.awaitUninterruptibly();

        executorService.shutdownNow();
    } 
                            #location 32 
                            #vulnerability type THREAD_SAFETY_VIOLATION