I wrote a Publisher class in java in order to send messages over a topic.

package com.jms.jms_ps;

import java.util.Properties;
import javax.naming.*;
import javax.jms.*;

/**
 *
 * @author achref
 */
public class Publisher {
    
    Context ctx;
    TopicConnectionFactory connectionFactory;
    Topic topic;
    TopicConnection connection;
    TopicSession session;
    
    TopicPublisher publisher;
    
    
    Publisher() throws NamingException{
        Properties props = new Properties();
        props.setProperty(Context.INITIAL_CONTEXT_FACTORY, "org.apache.activemq.jndi.ActiveMQInitialContextFactory");
            props.setProperty(Context.PROVIDER_URL, "tcp://localhost:61616");
            
        ctx = new InitialContext(props);
        
        connectionFactory = (TopicConnectionFactory) ctx.lookup("ConnectionFactory");
        topic = (Topic) ctx.lookup("dynamicTopics/myTopic");
        
    }
    
    void sendTextMessage(String msg) throws JMSException{
        connection = connectionFactory.createTopicConnection();
        session = connection.createTopicSession(true, 0);
        publisher = session.createPublisher(topic);
        
        TextMessage message = session.createTextMessage();
        message.setText(msg);
        
        connection.start();
        publisher.publish(message);
        connection.close();
        
    }
    
}

The problem is every time I try to send a message it doesn't add to my topic (Messages Enqueued is equal to zero) and therefore a subscriber receives nothing. ActiveMQ console

CodePudding user response：

You are sending a message in a transacted mode, but not committing the transaction. Ack mode = 0 is Session.TRANSACTED. You need to invoke session.commit() to permit the broker to deliver messages to the topic, or choose a different Acknowledgement mode for your use case.