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layout: default_md title: FAQ title-class: page-title-activemq5 type: activemq5

Here are a list of commonly asked questions and answers. If you have any questions which are not on this list, please talk to us on the forums.

We welcome contributions and this entire website is a wiki that you can edit so please join in and help us make the documentation better!

General

General questions about ActiveMQ

• Can I get commercial support
• How can I get help
• How can I get the source code from subversion
• How does ActiveMQ compare to AMQP
• How does ActiveMQ compare to Artemis
• How does ActiveMQ compare to Fuse Message Broker
• How does ActiveMQ compare to JBossMQ
• How does ActiveMQ compare to Mantaray
• How does ActiveMQ compare to Mule
• How does ActiveMQ compare to Spread Toolkit
• How does OpenWire compare to Stomp
• How does the website work
• How do I avoid Maven downloading latest jars
• How do I build but disable the unit tests
• How do I compile from the source
• How do I edit the website
• How fast is ActiveMQ
• Should I run ActiveMQ on Windows in a directory with spaces
• What is ActiveMQ
• What is the license
• What jars do I need
• What open source integration solution works best with ActiveMQ
• What platforms does ActiveMQ support
• What version should I use

JMS

Questions on using the JMS API and MOM in general

• Can I modify messages on a queue
• Can I send and receive messages concurrently on one JMS Connection
• Can you browse a topic
• How do durable queues and topics work
• How does a Queue compare to a Topic
• How does ConnectionFactory relate to the Broker
• How does JMS compare with email
• How do I consume a specific message
• How do I get started with JMS
• How do I make messages durable
• How do I send messages to different Destinations from a single MessageProducer
• How do I use JMS efficiently
• How should I implement request response with JMS
• How To Unit Test JMS Code
• Multiple consumers on a queue
• Should I use transactions
• Should I use XA
• What are administered objects

Using Apache ActiveMQ

Questions on using Apache ActiveMQ

• ActiveMQ Command Line Tools Reference
• Are destinations case sensitive
• Can I send really large files over ActiveMQ
• Can I use ActiveMQ 5.x or later on Java 1.4
• Can two brokers share the same database
• Does ActiveMQ support clustering
• How can I avoid serialization of Objects in ObjectMessage
• How can I get a list of the topics and queues in a broker
• How can I make ActiveMQ faster
• How can I monitor ActiveMQ
• How can I monitor the connection with the broker
• How can I see what destinations are used
• How can I support auto reconnection
• How can I support priority queues
• How can I use different network protocols
• How do distributed queues work
• How do I access ActiveMQ from C
• How do I access ActiveMQ from CSharp or dotNet
• How do I access ActiveMQ from Ruby, Perl, Python, PHP
• How do I bridge different JMS providers
• How do I change dispatch policy
• How do I change the logging
• How do I connect to one of a number of message brokers
• How do I create new destinations
• How do I delete a destination
• How do I disable logging
• How do I embed a Broker inside a Connection
• How do I enable asynchronous sending
• How do I enable debug logging
• How do I find the Size of a Queue
• How do I preserve order of messages
• How do I purge a queue
• How do I restart embedded broker
• How do I restrict connections from creating new queues or topics
• How do I run a broker
• How do I set the message expiration
• How do I turn off creating an embedded ActiveMQ broker when using the VM transport
• How do I unack the message with Stomp
• How do I use ActiveMQ using in JVM messaging
• How do I use durable subscribers in a network of brokers
• How do I use Ivy with ActiveMQ
• How do I use log4j JMS appender with ActiveMQ
• How do I use SSL
• How do Message Groups compare to Selectors
• How do multiple transports work
• How Do Transactions Work
• How lightweight is sending a message
• How should I package applications using Camel and ActiveMQ
• How should I use the VM transport
• How to deal with large number of threads in clients
• How to disable auto destination creation
• I see NC_ client-ids, what does that mean
• Should I deploy Enterprise Integration Patterns in the broker or another application
• Should I deploy the broker inside my JVM or AppServer
• What are those topics ActiveMQ.Advisory
• What happens with a fast producer and slow consumer
• What is the difference between a Virtual Topic and a Composite Destination
• What is the difference between discovery, multicast and zeroconf
• What is the Prefetch Limit For?
• While posting large binary file to activeMQ, is there a way to measure its progress

Configuration

Questions on configuring ActiveMQ's JMS client or the Message Broker

• How can I enable detailed logging
• How does XBean compare to Spring 2
• How do I configure 10s of 1000s of Queues in a single broker
• How do I configure ActiveMQ to hold 100s of millions of Queue Messages
• How do I configure ActiveMQ to use AIO server transport
• How do I configure automatic reconnection
• How do I configure distributed queues or topics
• How do I configure the queues I want
• How do I define a local address and local port for TCP or SSL
• How do I disable persistence
• How do I run ActiveMQ under the Kaffe JVM
• How to configure a new database
• How to deploy activemq-ra-version.rar to weblogic
• How to disable multicast discovery

Persistence Questions

Questions relating to long term persistence of messages.

• Are messages read directly from the journal
• Does ActiveMQ support my SQL database
• How does journaling work with multiple brokers
• How does the journal work
• How do I back-up KahaDB
• How do I change the message store directory for an embedded broker
• Is there a specified size of the journal
• What happens when the journal size is exceeded
• What is the difference between persistent and non-persistent delivery

Errors

Questions on specific kinds of errors. If you have seen a specific exception then check the Exceptions

• Could not find PacketReader for packet type - UNKNOWN PACKET TYPE
• Exceptions
  • certificate_unknown
  • IOException - could not find class for resource
  • java.io.InterruptedIOException
  • java.io.IOException Failed to create database ‘derbydb’, see the next exception for details
  • java.lang.NoSuchMethodError
  • java.lang.NoSuchMethodException org.activemq.ra.ActiveMQResourceAdapter.setUseEmbeddedBroker
  • java.lang.OutOfMemory
  • javax.jms.JMSException - Wire format negociation timeout - peer did not send his wire format.
  • JAXB 2.0 API is being loaded from the bootstrap classloader, but this RI () needs 2.1 API.
  • JAXB 2.0 API is being loaded from the bootstrap classloader, but this RI (xxx) needs 2.1 API
  • Journal is already opened by this application
  • NoClassDefFoundError - org.springframework.core.io.Resource
  • No suitable driver
• I am having problems with the Spring JmsTemplate
• I am not receiving any messages, what is wrong
• I cannot connect to ActiveMQ from JConsole
• I do not receive messages in my second consumer
• I get errors building the code whats wrong
• log4j-WARN No appenders could be found for logger
• Multicast - Watch out for IPV6 vs IPV4 support on your operating system or distribution or network
• My producer blocks
• onMessage method of MessageListener is never called
• Resource Adapter does not seem to pool connections
• Slow networks drop large messages
• The Broker will not start
• The vm transport starts a broker before my configured broker starts
• Why do I not get all of the messages I sent
• Why do I not receive messages on my durable topic subscription
• Why do KahaDB log files remain after cleanup

Developing ActiveMQ

Questions for developers wishing to extend or enhance Apache ActiveMQ

• How can I add a new type of transport
• How can I contribute
• How do I add my own plugins
• How do I debug ActiveMQ from my IDE

Terminology

A list of the various messaging related terms and acronyms.

• DR
• HA
• Latency
• MOM
• QoS
• SEDA
• Throughput