For a long time Java Messaging Service has been the API to handle messaging systems in the Java World, and now the messaging ecosystem is moving to the next generation of streaming services like Apache Pulsar. Why? Because Pulsar is free, Open Source, Cloud Native and it comes with cool new features that are not well supported by traditional JMS vendors. In this session you will see how to use Pulsar in a JakartaEE Web Application deployed on Apache TomEE via the JMS/EJB API, without installing any additional components to your cluster.

1. Using the JMS 2.0 API with Apache
Pulsar
Enrico Olivelli
DataStax - Luna Streaming Team
Member of Apache Pulsar, Apache BookKeeper and Apache ZooKeeper PMC,
Apache Curator VP

2. Agenda
● Introduction to the Java Messaging Service API
● Benefits of Apache Pulsar for JMS/JavaEE applications
● Mapping JMS to Pulsar
● Code samples: standard Java code
● Live Demo using EJBs and Apache TomEE®
2

3. Java Messaging Service API - Messaging for JavaEE
3
JMS is a set of simple API to interact with Messaging Systems:
- Produce and Consume Messages
- Manage Subscriptions
- Transactions
JDBC
JMS
SQL Database
Messaging
System

4. Java Messaging Service API - Core Concepts
4
JMS Concepts:
- Destinations: Queues and Topics
- Messages
- Producers and Consumers
- Connections and Sessions (JMSContext in 2.0)
Destination
Queue/Topi
c
Producer
Producer
Consumer
Consumer
Consumer
Producer
Send Message
Receive
Message

5. Java Messaging Service API - Destinations and clients
5
Destinations:
- Queue:
- Each message is received by one Consumer
- Browseable
- Topic:
- Multiple subscriptions
- Messages dispatched according to the Subscription Type
Consumer styles:
- Blocking receive() method, Application driven (no “async” receive)
- MessageListener method, JMS Driver driven
Producer styles:
- Blocking send() method
- Asynchronous send() with CompletionListener

6. Java Messaging Service API - Administrative operations
6
JMS does not cover administrative operations:
- Manage destinations
- Manage Connection properties
- Define Security Model
- Define Resource Limits
- Configure Quality of Service
The API deals only with Administered Objects:
- Destinations: Queue and Topic references
- ConnectionFactory: The “client” that allows you to connect to the system

7. Java Messaging Service API - interactions with JavaEE
7
In a JavaEE application you use Enterprise Java Beans (EJB) components
- Stateful/Stateless EJBs, used in:
- WebServlets
- WebServices (JAX-RS/JAX-WS endpoints)
- Background tasks (@Schedule)
- MessageDriven beans
- Activated by the container when receiving a message from a
Connector
The JavaEE container provides support for :
- Lifecycle management/pooling
- Context Dependency Injection (CDI)
- Transactions support
- Standard APIs to interact with the rest of the system

8. Java Messaging Service API - ResourceAdapters
8
You can extend a JavaEE container using ResourceAdapters (RA).
Key points:
- Deploy a .rar file that contains the code
- Configure the RA
- Allow you to create Administered objects that conform to standard
APIs, implemented by the core in the RA:
- javax.jms.ConnectionFactory
- javax.jms.Queue
- javax.jms.Topic
- Usually such objects are bound in a JNDI registry provided by the
container
How to deploy the .rar file and how to create the Objects is still specific to
the container.

9. Apache Pulsar - benefits for a JavaEE application
9
● Blazing performance: Millions of JMS messages with low latency.
● Horizontal scalability and object storage offloading: You can scale up or down
compute and storage independently.
● Consolidation: You can consolidate JMS applications spread across multiple
legacy JMS brokers onto a single Pulsar installation.
● Message replay: Applications to travel back in time and replay previously
consumed messages to recover from misconfiguration issues, recover from
bugs in application code, and test new applications against real data.
● Geo-replication: You can easily replicate your messages to other locations for
disaster recovery or global distribution.
● Future readiness: Support traditional messaging workloads, but you also log
collection, microservices integration, event streaming, and event sourcing.

10. Apache Pulsar - Basic Architecture
10
Bookies (scalable storage)
Brokers (stateless)
ZooKeeper
(metadata)
Proxy
(optional)
Pulsar Functions Workers Pulsar IO Connectors
Python
Producers
JMS
Go
C++
Java
Python
Consumers
JMS
Go
C++
Java
Cassandra
Enterprise
Services
Elastic
Search
Every component is
Horizontally Scalable
Dynamic
addition/removal of
components without
service interruption
GCS
S3
Object Storage

11. Apache Pulsar - Topics and Subscriptions
11
Unified Model for Messaging:
- Topics:
- Persistent/Non-Persistent
- Partitioned/Non-Partitioned
- Tenants and Namespaces:
- Logical and physical isolation of resources
- Fine grained configuration (topic/namespace/tenant/system
levels)
- Subscription modes:
- Exclusive, Failover, Shared, Key Shared
- Subscription types:
- Durable, Non-Durable
- Producer modes:
- Normal, Exclusive

12. Mapping the Pulsar to the JMS Model
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JMS Concepts can be easily mapped to the Pulsar Model:
- JMS Topic -> Pulsar topic
- JMS Queue -> Pulsar topic with only one “shared” durable subscription
- JMS Message -> Pulsar Message
Consumer types:
- Consumer -> Pulsar Exclusive Non-Durable Subscription with unknown name
- DurableConsumer -> Pulsar Exclusive Durable Subscription
- DurableSubscriber -> Pulsar Exclusive Durable Subscription
- SharedConsumer -> Pulsar Shared Non-Durable Subscription
- SharedDurableConsumer -> Pulsar Shared Durable Subscription
No need for additional Proxies or Pulsar protocol handlers
The mapping is managed automatically on the JMS Client library

13. Connect to Pulsar using the JMS API from JavaSE
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Steps to connect to Pulsar using the JMS API in a JavaSE application:
# step 1: create the ConnectionFactory (this is the only Pulsar specific code)
Map<String, Object> configuration = new HashMap<>();
configuration.put("webServiceUrl", "http://localhost:8080");
configuration.put("brokerServiceUrl", "pulsar://localhost:6650");
ConnectionFactory factory = new PulsarConnectionFactory(configuration);
# step 2: write and read some message
try (JMSContext context = factory.createContext()) {
Destination destination = context.createQueue("test");
context.createProducer().send(destination, "text");
try (JMSConsumer consumer = context.createConsumer(destination)) {
String message = consumer.receiveBody(String.class);
...

14. Live Demo - Producer Code - JavaEE - Singleton EJB
14
This is a simple EJB that send a JMS TextMessage using the JMSContext API
# Producer application
@Singleton
public class Timer {
@Resource(name = "pulsar-javax.jms.ConnectionFactory")
ConnectionFactory factory;
@Resource(lookup = "openejb:Resource/FooQueue")
Queue queue;
@Schedule(....)
public void send() {
try (JMSContext context = factory.createContext()) {
context.createProducer().send(queue, “test”);
}
Provided by the container

15. Live Demo - Consumer code - JavaEE - MessageDriver
bean
15
This is a simple EJB that consumes messages from a Pulsar Topic.
Messages are acknowledged automatically in case of successful processing.
# Consumer application
@MessageDriven(activationConfig = {
@ActivationConfigProperty(propertyName="destination",
propertyValue="lookup://openejb:Resource/FooQueue") })
public class JMSListener implements MessageListener {
public void onMessage(final Message message) {
String contents = message.getBody(String.class);
System.out.println("Received message '" contents
+ "' from destination " + message.getJMSDestination());
}
Provided by the container

16. Live Demo - Apache TomEE configuration
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In Apache TomEE you can define the configuration for the Pulsar Resource Adapter and create the FooQueue resource
# conf/system.properties
# deploy the RA (Resource Adapter)
ra = new://Deployments?jar=rars/pulsarra.rar
# binding with a Pulsar cluster is decided by the Administrator
pulsarRA.Configuration = {"brokerServiceUrl":"pulsar://localhost:6650",
"webServiceUrl":"http://localhost:8080"}
# configure the queue (logical JNDI name is openejb:Resource/FooQueue)
FooQueue=new://Resource?type=javax.jms.Queue
# binding with the Physical queue foo-queue is decided by the Administrator
FooQueue.destination=foo-queue

17. Live demo
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JavaEE container:
- Using Apache TomEE 8.0.6
- Deploy the Pulsar Resource Adapter (Fast JMS for Pulsar)
- https://github.com/datastax/pulsar-jms/tree/master/resource-adapter
- Create an Administered Object (a javax.jms.Queue)
Applications:
- One application with a @MessageDriver EJB that Consumes a Pulsar topic as a JMSQueue
- One application with a @Singleton EJB that produces messages
- Run Pulsar on local machine or on Free Astra Streaming Hosted account
Live Demo
https://github.com/eolivelli/pulsar-jms-examples

18. Wrapping up
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Java Messaging Service API and JavaEE:
- JMS is for Messaging Systems what JDBC is for Databases
- You can easily switch between from one JMS vendor to another
- The ResourceAdapter allows the container to Connect to external systems
- Configuration and Administration is container specific
Apache Pulsar:
- Pulsar is a Cloud Native Messaging System with built-in Multi-Tenancy and GeoReplication
- Pulsar components are horizontally scalable, with cold data offloading
- Pulsar is open source, with a vibrant community - no vendor lock-in
- It very easy to switch to Pulsar if you are already using JMS
Using Pulsar in a Java/JavaEE application via JMS is easy:
- Use the JMS Driver and connect from your Java program
- Deploy the Resource Adapter to integrate with your JavaEE® or JakartaEE® server
- Fast JMS for Apache Pulsar is Open Source and ready to use out-of-the-box

19. References
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LinkedIn - linkedin.com/in/enrico-olivelli-984b7874/
Twitter: twitter.com/eolivelli
Apache Pulsar Community: pulsar.apache.org/en/contact/ (Slack, ML…)
References:
Apache Pulsar: github.com/apache/pulsar (ASLv2)
Fast JMS for Apache Pulsar - github.com/datastax/pulsar-jms (ASLv2)
Jakarta JMS 2.0 speficifications - jakarta.ee/specifications/messaging/2.0/

20. Thank you !
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We are hiring: https://www.datastax.com/company/careers