Translations: Sample Java Programs/73/en

private void process() throws MalformedURLException {

       URL remoteUrl = new URL("http://localhost:26876/nxt");
       JO response;
       String token = null;
       try {
           // Monitor the blockchain for a new block
           response = EventRegisterCall.create().event("Block.BLOCK_PUSHED").remote(remoteUrl).call();
           Logger.logInfoMessage("EventRegisterCall add %s", response.toJSONString());
           if (!response.isExist("token")) {
               // Registration failed
               return;
           }
           token = response.getString("token");
           JA events;
           // Wait for the next event. The while loop is not necessary but serves as a good practice in order not to
           // keep and Http request open for a long time.
           while (true) {
               // Wait up to 1 second for the event to occur
               response = EventWaitCall.create().timeout("1").token(token).remote(remoteUrl).call();
               Logger.logInfoMessage("EventWaitCall %s", response.toJSONString());
               events = response.getArray("events");
               if (events.size() > 0) {
                   // If the event occurred stop waiting
                   break;
               }
           }
           // At this point the events array may include more than one event.
           events.objects().forEach(e -> Logger.logInfoMessage("" + e));
       } finally {
           if (token != null) {
               // Unregister the event listener
               response = EventRegisterCall.create().token(token).remove("true").remote(remoteUrl).call();
               Logger.logInfoMessage("EventRegisterCall remove %s", response.toJSONString());
           }
       }
   }

} </syntaxhighlight>