The Apache ActiveMQ Artemis distribution comes with over 90 run out-of-the-box examples demonstrating many of the features.
The examples are available in the distribution, in the examples
directory. Examples are split into JMS and core examples. JMS examples
show how a particular feature can be used by a normal JMS client. Core
examples show how the equivalent feature can be used by a core messaging
client.
A set of Java EE examples are also provided which need WildFly installed to be able to run.
To run a JMS example, simply cd into the appropriate example directory
and type mvn verify -Pexample (For details please read the readme.html in each
example directory).
Here's a listing of the examples with a brief description.
This example shows how you can send a message to a mobile device by leveraging AeroGears push technology which provides support for different push notification technologies like Google Cloud Messaging, Apple's APNs or Mozilla's SimplePush.
This example shows you how to send and receive JMS messages from an Applet.
Apache ActiveMQ Artemis also supports Application-Layer failover, useful in the case that replication is not enabled on the server side.
With Application-Layer failover, it's up to the application to register
a JMS ExceptionListener with Apache ActiveMQ Artemis which will be called by Apache ActiveMQ Artemis
in the event that connection failure is detected.
The code in the ExceptionListener then recreates the JMS connection,
session, etc on another node and the application can continue.
Application-layer failover is an alternative approach to High Availability (HA). Application-layer failover differs from automatic failover in that some client side coding is required in order to implement this. Also, with Application-layer failover, since the old session object dies and a new one is created, any uncommitted work in the old session will be lost, and any unacknowledged messages might be redelivered.
The bridge example demonstrates a core bridge deployed on one server,
which consumes messages from a local queue and forwards them to an
address on a second server.
Core bridges are used to create message flows between any two Apache ActiveMQ Artemis servers which are remotely separated. Core bridges are resilient and will cope with temporary connection failure allowing them to be an ideal choice for forwarding over unreliable connections, e.g. a WAN.
The browser example shows you how to use a JMS QueueBrowser with
Apache ActiveMQ Artemis.
Queues are a standard part of JMS, please consult the JMS 1.1 specification for full details.
A QueueBrowser is used to look at messages on the queue without
removing them. It can scan the entire content of a queue or only
messages matching a message selector.
The client-kickoff example shows how to terminate client connections
given an IP address using the JMX management API.
The client-side-failoverlistener example shows how to register a
listener to monitor failover events
The client-side-load-balancing example demonstrates how sessions
created from a single JMS Connection can be created to different nodes
of the cluster. In other words it demonstrates how Apache ActiveMQ Artemis does
client-side load-balancing of sessions across the cluster.
This example demonstrates a clustered JMS durable subscription
This is similar to the message grouping example except that it demonstrates it working over a cluster. Messages sent to different nodes with the same group id will be sent to the same node and the same consumer.
The clustered-queue example demonstrates a JMS queue deployed on two
different nodes. The two nodes are configured to form a cluster. We then
create a consumer for the queue on each node, and we create a producer
on only one of the nodes. We then send some messages via the producer,
and we verify that both consumers receive the sent messages in a
round-robin fashion.
The clustered-jgroups example demonstrates how to form a two node
cluster using JGroups as its underlying topology discovery technique,
rather than the default UDP broadcasting. We then create a consumer for
the queue on each node, and we create a producer on only one of the
nodes. We then send some messages via the producer, and we verify that
both consumers receive the sent messages in a round-robin fashion.
The clustered-standalone example demonstrates how to configure and
starts 3 cluster nodes on the same machine to form a cluster. A
subscriber for a JMS topic is created on each node, and we create a
producer on only one of the nodes. We then send some messages via the
producer, and we verify that the 3 subscribers receive all the sent
messages.
This example demonstrates how to configure a cluster using a list of connectors rather than UDP for discovery
This example demonstrates how to set up a cluster where cluster connections are one way, i.e. server A -> Server B -> Server C
The clustered-topic example demonstrates a JMS topic deployed on two
different nodes. The two nodes are configured to form a cluster. We then
create a subscriber on the topic on each node, and we create a producer
on only one of the nodes. We then send some messages via the producer,
and we verify that both subscribers receive all the sent messages.
With Apache ActiveMQ Artemis you can specify a maximum consume rate at which a JMS MessageConsumer will consume messages. This can be specified when creating or deploying the connection factory.
If this value is specified then Apache ActiveMQ Artemis will ensure that messages are never consumed at a rate higher than the specified rate. This is a form of consumer throttling.
The dead-letter example shows you how to define and deal with dead
letter messages. Messages can be delivered unsuccessfully (e.g. if the
transacted session used to consume them is rolled back).
Such a message goes back to the JMS destination ready to be redelivered. However, this means it is possible for a message to be delivered again and again without any success and remain in the destination, clogging the system.
To prevent this, messaging systems define dead letter messages: after a specified unsuccessful delivery attempts, the message is removed from the destination and put instead in a dead letter destination where they can be consumed for further investigation.
The delayed-redelivery example demonstrates how Apache ActiveMQ Artemis can be
configured to provide a delayed redelivery in the case a message needs
to be redelivered.
Delaying redelivery can often be useful in the case that clients regularly fail or roll-back. Without a delayed redelivery, the system can get into a "thrashing" state, with delivery being attempted, the client rolling back, and delivery being re-attempted in quick succession, using up valuable CPU and network resources.
Apache ActiveMQ Artemis diverts allow messages to be transparently "diverted" or copied from one address to another with just some simple configuration defined on the server side.
The durable-subscription example shows you how to use a durable
subscription with Apache ActiveMQ Artemis. Durable subscriptions are a standard part of
JMS, please consult the JMS 1.1 specification for full details.
Unlike non-durable subscriptions, the key function of durable subscriptions is that the messages contained in them persist longer than the lifetime of the subscriber - i.e. they will accumulate messages sent to the topic even if there is no active subscriber on them. They will also survive server restarts or crashes. Note that for the messages to be persisted, the messages sent to them must be marked as durable messages.
The embedded example shows how to embed JMS within your own code using
POJO instantiation and no config files.
The embedded example shows how to embed JMS within your own code using
regular Apache ActiveMQ Artemis XML files.
The expiry example shows you how to define and deal with message
expiration. Messages can be retained in the messaging system for a
limited period of time before being removed. JMS specification states
that clients should not receive messages that have been expired (but it
does not guarantee this will not happen).
Apache ActiveMQ Artemis can assign an expiry address to a given queue so that when messages are expired, they are removed from the queue and sent to the expiry address. These "expired" messages can later be consumed from the expiry address for further inspection.
This examples shows how to build the activemq resource adapters a rar for deployment in other Application Server's
The http-transport example shows you how to configure Apache ActiveMQ Artemis to use
the HTTP protocol as its transport layer.
Usually, JMS Objects such as ConnectionFactory, Queue and Topic
instances are looked up from JNDI before being used by the client code.
This objects are called "administered objects" in JMS terminology.
However, in some cases a JNDI server may not be available or desired. To come to the rescue Apache ActiveMQ Artemis also supports the direct instantiation of these administered objects on the client side so you don't have to use JNDI for JMS.
Apache ActiveMQ Artemis allows an application to use an interceptor to hook into the messaging system. Interceptors allow you to handle various message events in Apache ActiveMQ Artemis.
The jaas example shows you how to configure Apache ActiveMQ Artemis to use JAAS for
security. Apache ActiveMQ Artemis can leverage JAAS to delegate user authentication and
authorization to existing security infrastructure.
The jms-auto-closeable example shows how JMS resources, such as
connections, sessions and consumers, in JMS 2 can be automatically
closed on error.
The jms-completion-listener example shows how to send a message
asynchronously to Apache ActiveMQ Artemis and use a CompletionListener to be notified
of the Broker receiving it.
The jms-brige example shows how to setup a bridge between two
standalone Apache ActiveMQ Artemis servers.
The jms-context example shows how to send and receive a message to a
JMS Queue using Apache ActiveMQ Artemis by using a JMS Context.
A JMSContext is part of JMS 2.0 and combines the JMS Connection and Session Objects into a simple Interface.
The jms-shared-consumer example shows you how can use shared consumers
to share a subscription on a topic. In JMS 1.1 this was not allowed and
so caused a scalability issue. In JMS 2 this restriction has been lifted
so you can share the load across different threads and connections.
The jmx example shows how to manage Apache ActiveMQ Artemis using JMX.
The large-message example shows you how to send and receive very large
messages with Apache ActiveMQ Artemis. Apache ActiveMQ Artemis supports the sending and receiving of
huge messages, much larger than can fit in available RAM on the client
or server. Effectively the only limit to message size is the amount of
disk space you have on the server.
Large messages are persisted on the server so they can survive a server restart. In other words Apache ActiveMQ Artemis doesn't just do a simple socket stream from the sender to the consumer.
The last-value-queue example shows you how to define and deal with
last-value queues. Last-value queues are special queues which discard
any messages when a newer message with the same value for a well-defined
last-value property is put in the queue. In other words, a last-value
queue only retains the last value.
A typical example for last-value queue is for stock prices, where you are only interested by the latest price for a particular stock.
The management example shows how to manage Apache ActiveMQ Artemis using JMS Messages
to invoke management operations on the server.
The management-notification example shows how to receive management
notifications from Apache ActiveMQ Artemis using JMS messages. Apache ActiveMQ Artemis servers emit
management notifications when events of interest occur (consumers are
created or closed, addresses are created or deleted, security
authentication fails, etc.).
The message-counters example shows you how to use message counters to
obtain message information for a JMS queue.
The message-group example shows you how to configure and use message
groups with Apache ActiveMQ Artemis. Message groups allow you to pin messages so they
are only consumed by a single consumer. Message groups are sets of
messages that has the following characteristics:
Messages in a message group share the same group id, i.e. they have same JMSXGroupID string property values
The consumer that receives the first message of a group will receive all the messages that belongs to the group
The message-group2 example shows you how to configure and use message
groups with Apache ActiveMQ Artemis via a connection factory.
Message Priority can be used to influence the delivery order for messages.
It can be retrieved by the message's standard header field 'JMSPriority' as defined in JMS specification version 1.1.
The value is of type integer, ranging from 0 (the lowest) to 9 (the highest). When messages are being delivered, their priorities will effect their order of delivery. Messages of higher priorities will likely be delivered before those of lower priorities.
Messages of equal priorities are delivered in the natural order of their arrival at their destinations. Please consult the JMS 1.1 specification for full details.
This example demonstrates how to set up a live server with multiple backups
This example demonstrates how to set up a live server with multiple backups but forcing failover back to the original live server
By default, Apache ActiveMQ Artemis consumers buffer messages from the server in a
client side buffer before you actually receive them on the client side.
This improves performance since otherwise every time you called
receive() or had processed the last message in a
MessageListener onMessage() method, the Apache ActiveMQ Artemis client would have to
go the server to request the next message, which would then get sent to
the client side, if one was available.
This would involve a network round trip for every message and reduce performance. Therefore, by default, Apache ActiveMQ Artemis pre-fetches messages into a buffer on each consumer.
In some case buffering is not desirable, and Apache ActiveMQ Artemis allows it to be switched off. This example demonstrates that.
The non-transaction-failover example demonstrates two servers coupled
as a live-backup pair for high availability (HA), and a client using a
non-transacted JMS session failing over from live to backup when the
live server is crashed.
Apache ActiveMQ Artemis implements failover of client connections between live and backup servers. This is implemented by the replication of state between live and backup nodes. When replication is configured and a live node crashes, the client connections can carry and continue to send and consume messages. When non-transacted sessions are used, once and only once message delivery is not guaranteed and it is possible that some messages will be lost or delivered twice.
The Openwire example shows how to configure an Apache ActiveMQ Artemis server to
communicate with an Apache ActiveMQ Artemis JMS client that uses open-wire protocol.
The paging example shows how Apache ActiveMQ Artemis can support huge queues even
when the server is running in limited RAM. It does this by transparently
paging messages to disk, and depaging them when they are required.
Standard JMS supports three acknowledgement modes:AUTO_ACKNOWLEDGE, CLIENT_ACKNOWLEDGE, and
DUPS_OK_ACKNOWLEDGE. For a full description on these modes please
consult the JMS specification, or any JMS tutorial.
All of these standard modes involve sending acknowledgements from the client to the server. However in some cases, you really don't mind losing messages in event of failure, so it would make sense to acknowledge the message on the server before delivering it to the client. This example demonstrates how Apache ActiveMQ Artemis allows this with an extra acknowledgement mode.
The producer-rte-limit example demonstrates how, with Apache ActiveMQ Artemis, you
can specify a maximum send rate at which a JMS message producer will
send messages.
Apache ActiveMQ Artemis can be configured to accept requests from any AMQP client that
supports the 1.0 version of the protocol. This proton-j example shows
a simply qpid java 1.0 client example.
Apache ActiveMQ Artemis can be configured to accept requests from any AMQP client that supports the 1.0 version of the protocol. This example shows a simply proton ruby client that sends and receives messages
A simple example demonstrating a JMS queue.
The queue-message-redistribution example demonstrates message
redistribution between queues with the same name deployed in different
nodes of a cluster.
A simple example demonstrating a JMS queue requestor.
The queue-selector example shows you how to selectively consume
messages using message selectors with queue consumers.
The Reattach Node example shows how a client can try to reconnect to
the same server instead of failing the connection immediately and
notifying any user ExceptionListener objects. Apache ActiveMQ Artemis can be configured
to automatically retry the connection, and reattach to the server when
it becomes available again across the network.
An example showing how failback works when using replication, In this example a live server will replicate all its Journal to a backup server as it updates it. When the live server crashes the backup takes over from the live server and the client reconnects and carries on from where it left off.
An example showing how failback works when using replication, but this time with static connectors
An example showing how to configure multiple backups when using replication
An example showing how failover works with a transaction when using replication
A simple example showing the JMS request-response pattern.
An example showing how to use the Apache ActiveMQ Artemis Rest API
The scheduled-message example shows you how to send a scheduled
message to a JMS Queue with Apache ActiveMQ Artemis. Scheduled messages won't get
delivered until a specified time in the future.
The security example shows you how configure and use role based queue
security with Apache ActiveMQ Artemis.
The send-acknowledgements example shows you how to use Apache ActiveMQ Artemis's
advanced asynchronous send acknowledgements feature to obtain
acknowledgement from the server that sends have been received and
processed in a separate stream to the sent messages.
This example shows how to use embedded JMS using Apache ActiveMQ Artemis's Spring integration.
The ssl-enabled shows you how to configure SSL with Apache ActiveMQ Artemis to send
and receive message.
The static-selector example shows you how to configure an Apache ActiveMQ Artemis core
queue with static message selectors (filters).
The static-selector-jms example shows you how to configure an Apache ActiveMQ Artemis
queue with static message selectors (filters) using JMS.
The stomp example shows you how to configure an Apache ActiveMQ Artemis server to send
and receive Stomp messages.
The stomp example shows you how to configure an Apache ActiveMQ Artemis server to send
and receive Stomp messages via a Stomp 1.1 connection.
The stomp example shows you how to configure an Apache ActiveMQ Artemis server to send
and receive Stomp messages via a Stomp 1.2 connection.
The stomp-websockets example shows you how to configure an Apache ActiveMQ Artemis
server to send and receive Stomp messages directly from Web browsers
(provided they support Web Sockets).
The symmetric-cluster example demonstrates a symmetric cluster set-up
with Apache ActiveMQ Artemis.
Apache ActiveMQ Artemis has extremely flexible clustering which allows you to set-up servers in many different topologies. The most common topology that you'll perhaps be familiar with if you are used to application server clustering is a symmetric cluster.
With a symmetric cluster, the cluster is homogeneous, i.e. each node is configured the same as every other node, and every node is connected to every other node in the cluster.
A simple example demonstrating how to use a JMS temporary queue.
A simple example demonstrating a JMS topic.
Apache ActiveMQ Artemis supports topic hierarchies. With a topic hierarchy you can register a subscriber with a wild-card and that subscriber will receive any messages sent to an address that matches the wild card.
The topic-selector-example1 example shows you how to send message to a
JMS Topic, and subscribe them using selectors with Apache ActiveMQ Artemis.
The topic-selector-example2 example shows you how to selectively
consume messages using message selectors with topic consumers.
The transaction-failover example demonstrates two servers coupled as a
live-backup pair for high availability (HA), and a client using a
transacted JMS session failing over from live to backup when the live
server is crashed.
Apache ActiveMQ Artemis implements failover of client connections between live and backup servers. This is implemented by the sharing of a journal between the servers. When a live node crashes, the client connections can carry and continue to send and consume messages. When transacted sessions are used, once and only once message delivery is guaranteed.
The stop-server-failover example demonstrates failover of the JMS
connection from one node to another when the live server crashes using a
JMS non-transacted session.
The transactional example shows you how to use a transactional Session
with Apache ActiveMQ Artemis.
The xa-heuristic example shows you how to make an XA heuristic
decision through Apache ActiveMQ Artemis Management Interface. A heuristic decision is
a unilateral decision to commit or rollback an XA transaction branch
after it has been prepared.
The xa-receive example shows you how message receiving behaves in an
XA transaction in Apache ActiveMQ Artemis.
The xa-send example shows you how message sending behaves in an XA
transaction in Apache ActiveMQ Artemis.
To run a core example, simply cd into the appropriate example
directory and type ant
The embedded example shows how to embed the Apache ActiveMQ Artemis server within
your own code.