ExecutorService executor = Executors.newCachedThreadPool();
JmsSender jmsSender = JmsSender.getInstance();
jmsSender.connect();

for (int i = 1; i <= maxThreads; i++) {
      eventList = new ArrayList<>();
      eventList = generateEvents(eventList, app + i);
      executor.execute(new JmsProducer(app + i, queue, eventList));
}

executor.shutdown();

while (!executor.isShutdown()) {
}
        
jmsSender.disconnect();

executor.shutdown();
executor.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
jmsSender.disconnect();

@Override
    public void run() {
        System.out.println(name + " - " + jmsSender);
        eventList.forEach((event) -> {
            try {
                jmsSender.send(event, queue);
            } catch (JMSException ex) {
                Logger.getLogger(JmsProducer.class.getName())
                        .log(Level.SEVERE, null, ex);
            }
        });
    }

public void send(Event event, String queue) throws JMSException {
        MessageProducer producer = session.createProducer(
                session.createQueue(queue));
        
        producer.setDeliveryMode(DeliveryMode.PERSISTENT);
        producer.send(session.createObjectMessage(event));
    }