WildFly JMS topic consumer receives null value

Question

I am using WildFly 19 and a JMS topic application. After running this program it returns a null value.

try {
    final Properties env = new Properties();
    env.put(Context.INITIAL_CONTEXT_FACTORY, "org.wildfly.naming.client.WildFlyInitialContextFactory");
    env.put(Context.PROVIDER_URL, "http-remoting://127.0.0.1:8080");
    env.put(Context.SECURITY_PRINCIPAL, "jmsuser");
    env.put(Context.SECURITY_CREDENTIALS, "Password1!");
    namingContext = new InitialContext(env);

    ConnectionFactory connectionFactory = (ConnectionFactory) namingContext.lookup("jms/RemoteConnectionFactory");
    Destination destination = (Destination) namingContext .lookup("jms/topic/myTopic");
    context = connectionFactory.createContext("jmsuser", "Password1!");
    context.createProducer().send(destination, "mymeninsgh city topic !");
    System.out.println("Sent message successuflly ");

    JMSConsumer consumer = context.createConsumer(destination);
    String text = consumer.receiveBody(String.class, 5000);
    System.out.println("Received message with content " + text);

} catch (Exception e) {
    System.out.println(e.getMessage());
    throw e;
} finally {
    if (namingContext != null) {
        namingContext.close();
    }
    if (context != null) {
        context.close();
    }
}

WildFly topic configuration is :

After run this program it gives bellow error:

Sent message successuflly 
Received message with content null

How can solve this error (null)? How can I get actual value instead of null?

Answer 1

What you're seeing is the expected behavior since you're sending the message to a JMS topic before creating a consumer. This is because JMS topics follow publish/subscribe semantics which dictate that messages sent before any subscriptions are created get discarded.

You should either:

• Create your consumer first and then send the message.
• Send the message to a JMS queue.