Apache ActiveMQ Cheat Sheet

Overview

Apache ActiveMQ is an open-source, multi-protocol message broker written in Java. It supports JMS 1.1 and 2.0, AMQP, STOMP, MQTT, and OpenWire protocols, making it one of the most versatile message brokers available. ActiveMQ Classic is the long-standing version, while ActiveMQ Artemis is the next-generation broker with improved performance.

ActiveMQ provides persistent and non-persistent messaging, message groups, virtual destinations, composite destinations, and advanced clustering features. It integrates seamlessly with Java EE application servers and Spring Framework, and can be embedded directly into Java applications.

Installation

Using Docker

# ActiveMQ Classic
docker run -d --name activemq \
  -p 61616:61616 \
  -p 8161:8161 \
  apache/activemq-classic:latest

# ActiveMQ Artemis
docker run -d --name artemis \
  -p 61616:61616 \
  -p 8161:8161 \
  apache/activemq-artemis:latest

Linux / macOS Binary Install

# Download and extract
wget https://downloads.apache.org/activemq/5.18.3/apache-activemq-5.18.3-bin.tar.gz
tar -xzf apache-activemq-5.18.3-bin.tar.gz
cd apache-activemq-5.18.3

# Start the broker
./bin/activemq start

# Check status
./bin/activemq status

# Stop the broker
./bin/activemq stop

Web Console Access

# Default web console URL
# http://localhost:8161/admin
# Default credentials: admin / admin

Core Commands

Command	Description
`./bin/activemq start`	Start broker in background
`./bin/activemq console`	Start broker in foreground
`./bin/activemq stop`	Stop the broker
`./bin/activemq status`	Check broker status
`./bin/activemq restart`	Restart the broker
`./bin/activemq list`	List all running brokers
`./bin/activemq browse <queue>`	Browse messages in a queue
`./bin/activemq purge <queue>`	Purge all messages from a queue

Queue and Topic Management

CLI Operations

# Send a message to a queue
./bin/activemq producer --destination queue://TEST.QUEUE \
  --messageCount 100 --message "Hello ActiveMQ"

# Consume messages from a queue
./bin/activemq consumer --destination queue://TEST.QUEUE \
  --messageCount 100

# Send to a topic
./bin/activemq producer --destination topic://TEST.TOPIC \
  --messageCount 10

# Browse queue messages
./bin/activemq browse --amqurl tcp://localhost:61616 TEST.QUEUE

REST API

# List queues via Jolokia REST API
curl -u admin:admin \
  'http://localhost:8161/api/jolokia/read/org.apache.activemq:type=Broker,brokerName=localhost'

# Get queue stats
curl -u admin:admin \
  'http://localhost:8161/api/jolokia/read/org.apache.activemq:type=Broker,brokerName=localhost,destinationType=Queue,destinationName=TEST.QUEUE'

# Purge a queue via REST
curl -u admin:admin \
  'http://localhost:8161/api/jolokia/exec/org.apache.activemq:type=Broker,brokerName=localhost,destinationType=Queue,destinationName=TEST.QUEUE/purge'

Configuration

Main Broker Config (`conf/activemq.xml`)

<beans>
  <broker xmlns="http://activemq.apache.org/schema/core"
          brokerName="myBroker"
          dataDirectory="${activemq.data}">

    <!-- Transport connectors -->
    <transportConnectors>
      <transportConnector name="openwire" uri="tcp://0.0.0.0:61616"/>
      <transportConnector name="amqp" uri="amqp://0.0.0.0:5672"/>
      <transportConnector name="stomp" uri="stomp://0.0.0.0:61613"/>
      <transportConnector name="mqtt" uri="mqtt://0.0.0.0:1883"/>
    </transportConnectors>

    <!-- Persistence adapter -->
    <persistenceAdapter>
      <kahaDB directory="${activemq.data}/kahadb"
              journalMaxFileLength="32mb"/>
    </persistenceAdapter>

    <!-- Memory limits -->
    <systemUsage>
      <systemUsage>
        <memoryUsage><memoryUsage percentOfJvmHeap="70"/></memoryUsage>
        <storeUsage><storeUsage limit="100 gb"/></storeUsage>
        <tempUsage><tempUsage limit="50 gb"/></tempUsage>
      </systemUsage>
    </systemUsage>

    <!-- Destination policies -->
    <destinationPolicy>
      <policyMap>
        <policyEntries>
          <policyEntry queue=">" memoryLimit="256mb"
                       producerFlowControl="true"/>
          <policyEntry topic=">" memoryLimit="256mb"/>
        </policyEntries>
      </policyMap>
    </destinationPolicy>
  </broker>
</beans>

Authentication (`conf/jetty-realm.properties`)

# username: password, role
admin: admin123, admin
user: user123, user
producer: prod123, producer
consumer: cons123, consumer

Advanced Usage

Network of Brokers (Clustering)

<!-- In activemq.xml — broker A connects to broker B -->
<networkConnectors>
  <networkConnector name="A-to-B"
    uri="static:(tcp://brokerB:61616)"
    duplex="true"
    decreaseNetworkConsumerPriority="true"
    networkTTL="2"
    dynamicOnly="true"/>
</networkConnectors>

Virtual Destinations

<!-- Route topic messages to individual consumer queues -->
<destinationInterceptors>
  <virtualDestinationInterceptor>
    <virtualDestinations>
      <compositeQueue name="MY.QUEUE">
        <forwardTo>
          <queue physicalName="QUEUE.A"/>
          <queue physicalName="QUEUE.B"/>
        </forwardTo>
      </compositeQueue>
      <virtualTopic name="VirtualTopic.>"
        prefix="Consumer.*."
        selectorAware="false"/>
    </virtualDestinations>
  </virtualDestinationInterceptor>
</destinationInterceptors>

Dead Letter Queue Configuration

<policyEntry queue=">">
  <deadLetterStrategy>
    <individualDeadLetterStrategy queuePrefix="DLQ."
      useQueueForQueueMessages="true"
      processExpired="true"
      processNonPersistent="true"/>
  </deadLetterStrategy>
  <redeliveryPolicy maximumRedeliveries="5"
    initialRedeliveryDelay="1000"
    redeliveryDelay="5000"
    backOffMultiplier="2"
    useExponentialBackOff="true"/>
</policyEntry>

Monitoring

JMX Monitoring

# Connect via JConsole
jconsole service:jmx:rmi:///jndi/rmi://localhost:1099/jmxrmi

# Key MBeans
# org.apache.activemq:type=Broker — broker stats
# org.apache.activemq:type=Queue — queue metrics
# org.apache.activemq:type=Topic — topic metrics

Key Metrics to Monitor

Metric	Description
`QueueSize`	Number of pending messages
`EnqueueCount`	Total messages enqueued
`DequeueCount`	Total messages dequeued
`ConsumerCount`	Active consumers
`ProducerCount`	Active producers
`MemoryPercentUsage`	Broker memory utilization
`StorePercentUsage`	Persistent store utilization
`DispatchCount`	Messages dispatched to consumers

Troubleshooting

Issue	Solution
Broker won’t start	Check `data/activemq.log` for port conflicts or permission errors
Messages stuck in queue	Verify consumers are connected; check `ConsumerCount` via JMX
Out of memory	Increase heap in `env` file; tune `memoryUsage` in config
Slow consumers	Enable producer flow control; add more consumer instances
KahaDB corruption	Stop broker, delete `data/kahadb/db.data`, restart (loses messages)
Web console inaccessible	Check Jetty config in `conf/jetty.xml`; verify port 8161 is free
Connection refused	Ensure transport connector is bound to correct interface
DLQ filling up	Review redelivery policy; investigate consumer processing errors