JMS Component

Using ActiveMQ

If you are using Apache ActiveMQ, you should prefer the ActiveMQ component as it has been optimized for ActiveMQ. All of the options and samples on this page are also valid for the ActiveMQ component.

Transacted and caching

See section Transactions and Cache Levels below if you are using transactions with JMS as it can impact performance.

The JMS component allows messages to be sent to (or consumed from) a JMS Queue or Topic. The implementation of the JMS Component uses Spring's JMS support for declarative transactions, using Spring's JmsTemplate for sending and a MessageListenerContainer for consuming.

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-jms</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

URI format

jms:[queue:|topic:]destinationName[?options]

Where destinationName is a JMS queue or topic name. By default, the destinationName is interpreted as a queue name. For example, to connect to the queue, FOO.BAR use:

jms:FOO.BAR

You can include the optional queue: prefix, if you prefer:

jms:queue:FOO.BAR

To connect to a topic, you must include the topic: prefix. For example, to
connect to the topic, Stocks.Prices, use:

jms:topic:Stocks.Prices

You append query options to the URI using the following format, ?option=value&option=value&...

Notes

Using ActiveMQ

The JMS component reuses Spring 2's JmsTemplate for sending messages. This is not ideal for use in a non-J2EE container and typically requires some caching in the JMS provider to avoid poor performance.

If you intend to use Apache ActiveMQ as your Message Broker - which is a good choice as ActiveMQ rocks :), then we recommend that you either:

Transactions and Cache Levels


If you are consuming messages and using transactions (transacted=true) then the default settings for cache level can impact performance.
If you are using XA transactions then you cannot cache as it can cause the XA transaction to not work properly.

If you are not using XA, then you should consider caching as it speeds up performance, such as setting cacheLevelName=CACHE_CONSUMER.

Through Camel 2.7.x, the default setting for cacheLevelName is CACHE_CONSUMER. You will need to explicitly set cacheLevelName=CACHE_NONE.
In Camel 2.8 onwards, the default setting for cacheLevelName is CACHE_AUTO. This default auto detects the mode and sets the cache level accordingly to:

So you can say the default setting is conservative. Consider using cacheLevelName=CACHE_CONSUMER if you are using non-XA transactions.

Durable Subscriptions

If you wish to use durable topic subscriptions, you need to specify both clientId and durableSubscriptionName. The value of the clientId must be unique and can only be used by a single JMS connection instance in your entire network. You may prefer to use Virtual Topics instead to avoid this limitation. More background on durable messaging here.

Message Header Mapping

When using message headers, the JMS specification states that header names must be valid Java identifiers. So, by default, Camel ignores any headers that do not match this rule. So try to name your headers as if they are valid Java identifiers. One benefit of doing this is that you can then use your headers inside a JMS Selector (whose SQL92 syntax mandates Java identifier syntax for headers).

A simple strategy for mapping header names is used by default. The strategy is to replace any dots and hyphens in the header name as shown below and to reverse the replacement when the header name is restored from a JMS message sent over the wire. What does this mean? No more losing method names to invoke on a bean component, no more losing the filename header for the File Component, and so on.

The current header name strategy for accepting header names in Camel is as follows:

Options

You can configure many different properties on the JMS endpoint which map to properties on the JMSConfiguration POJO.

Mapping to Spring JMS

Many of these properties map to properties on Spring JMS, which Camel uses for sending and receiving messages. So you can get more information about these properties by consulting the relevant Spring documentation.

The options are divided into two tables, the first one with the most common options used. The latter contains the rest.

Most commonly used options

Option Default Value Description
clientId null Sets the JMS client ID to use. Note that this value, if specified, must be unique and can only be used by a single JMS connection instance. It is typically only required for durable topic subscriptions. You may prefer to use Virtual Topics instead.
concurrentConsumers 1 Specifies the default number of concurrent consumers.
disableReplyTo false If true, a producer will behave like a InOnly exchange with the exception that JMSReplyTo header is sent out and not be suppressed like in the case of InOnly. Like InOnly the producer will not wait for a reply. A consumer with this flag will behave like InOnly. This feature can be used to bridge InOut requests to another queue so that a route on the other queue will send it�s response directly back to the original JMSReplyTo.
durableSubscriptionName null The durable subscriber name for specifying durable topic subscriptions. The clientId option must be configured as well.
maxConcurrentConsumers 1 Specifies the maximum number of concurrent consumers.
preserveMessageQos false Set to true, if you want to send message using the QoS settings specified on the message, instead of the QoS settings on the JMS endpoint. The following three headers are considered JMSPriority, JMSDeliveryMode, and JMSExpiration. You can provide all or only some of them. If not provided, Camel will fall back to use the values from the endpoint instead. So, when using this option, the headers override the values from the endpoint. The explicitQosEnabled option, by contrast, will only use options set on the endpoint, and not values from the message header.
replyTo null Provides an explicit ReplyTo destination, which overrides any incoming value of Message.getJMSReplyTo(). If you do Request Reply over JMS then read the section further below for more details.
replyToType null Camel 2.9: Allows for explicitly specifying which kind of strategy to use for replyTo queues when doing request/reply over JMS. Possible values are: Temporary, Shared, or Exclusive. By default Camel will use temporary queues. However if replyTo has been configured, then Shared is used by default. This option allows you to use exclusive queues instead of shared ones. See further below for more details, and especially the notes about the implications if running in a clustered environment.
requestTimeout 20000 Producer only: The timeout for waiting for a reply when using the InOut Exchange Pattern (in milliseconds). The default is 20 seconds. See below in section About time to live for more details. See also the requestTimeoutCheckerInterval option.
selector null Sets the JMS Selector, which is an SQL 92 predicate that is used to filter messages within the broker. You may have to encode special characters such as = as %3D Before Camel 2.3.0, we don't support this option in CamelConsumerTemplate
timeToLive null When sending messages, specifies the time-to-live of the message (in milliseconds). See below in section About time to live for more details.
transacted false

Specifies whether to use transacted mode for sending/receiving messages using the InOnly Exchange Pattern.

All the other options

Option Default Value Description
acceptMessagesWhileStopping false Specifies whether the consumer accept messages while it is stopping. You may consider enabling this option, if you start and stop JMS routes at runtime, while there are still messages enqued on the queue. If this option is false, and you stop the JMS route, then messages may be rejected, and the JMS broker would have to attempt redeliveries, which yet again may be rejected, and eventually the message may be moved at a dead letter queue on the JMS broker. To avoid this its recommended to enable this option.
acknowledgementModeName AUTO_ACKNOWLEDGE The JMS acknowledgement name, which is one of: TRANSACTED, CLIENT_ACKNOWLEDGE, AUTO_ACKNOWLEDGE, DUPS_OK_ACKNOWLEDGE
acknowledgementMode -1 The JMS acknowledgement mode defined as an Integer. Allows you to set vendor-specific extensions to the acknowledgment mode. For the regular modes, it is preferable to use the acknowledgementModeName instead.
allowNullBody true Camel 2.9.3/2.10.1: Whether to allow sending messages with no body. If this option is false and the message body is null, then an JMSException is thrown.
alwaysCopyMessage false If true, Camel will always make a JMS message copy of the message when it is passed to the producer for sending. Copying the message is needed in some situations, such as when a replyToDestinationSelectorName is set (incidentally, Camel will set the alwaysCopyMessage option to true, if a replyToDestinationSelectorName is set)
asyncConsumer false Camel 2.9: Whether the JmsConsumer processes the Exchange asynchronously. If enabled then the JmsConsumer may pickup the next message from the JMS queue, while the previous message is being processed asynchronously (by the Asynchronous Routing Engine). This means that messages may be processed not 100% strictly in order. If disabled (as default) then the Exchange is fully processed before the JmsConsumer will pickup the next message from the JMS queue. Note if transacted has been enabled, then asyncConsumer=true does not run asynchronously, as transactions must be executed synchronously (Camel 3.0 may support async transactions).
asyncStartListener false Camel 2.10: Whether to startup the JmsConsumer message listener asynchronously, when starting a route. For example if a JmsConsumer cannot get a connection to a remote JMS broker, then it may block while retrying and/or failover. This will cause Camel to block while starting routes. By setting this option to true, you will let routes startup, while the JmsConsumer connects to the JMS broker using a dedicated thread in asynchronous mode. If this option is used, then beware that if the connection could not be established, then an exception is logged at WARN level, and the consumer will not be able to receive messages; You can then restart the route to retry.
asyncStopListener false Camel 2.10: Whether to stop the JmsConsumer message listener asynchronously, when stopping a route.
autoStartup true Specifies whether the consumer container should auto-startup.
cacheLevelName - Sets the cache level by name for the underlying JMS resources. Possible values are: CACHE_AUTO, CACHE_CONNECTION, CACHE_CONSUMER, CACHE_NONE, and CACHE_SESSION. The default setting for Camel 2.8 and newer is CACHE_AUTO. For Camel 2.7.1 and older the default is CACHE_CONSUMER. See the Spring documentation and Transactions Cache Levels for more information.
cacheLevel - Sets the cache level by ID for the underlying JMS resources. See cacheLevelName option for more details.
consumerType Default The consumer type to use, which can be one of: Simple or Default. The consumer type determines which Spring JMS listener to use. Default will use org.springframework.jms.listener.DefaultMessageListenerContainer, Simple will use org.springframework.jms.listener.SimpleMessageListenerContainer. This option was temporary removed in Camel 2.7 and 2.8. But has been added back from Camel 2.9 onwards.
connectionFactory null The default JMS connection factory to use for the listenerConnectionFactory and templateConnectionFactory, if neither is specified.
deliveryPersistent true Specifies whether persistent delivery is used by default.
destination null Specifies the JMS Destination object to use on this endpoint.
destinationName null Specifies the JMS destination name to use on this endpoint.
destinationResolver null A pluggable org.springframework.jms.support.destination.DestinationResolver that allows you to use your own resolver (for example, to lookup the real destination in a JNDI registry).
disableTimeToLive false Camel 2.8: Use this option to force disabling time to live. For example when you do request/reply over JMS, then Camel will by default use the requestTimeout value as time to live on the message being sent. The problem is that the sender and receiver systems have to have their clocks synchronized, so they are in sync. This is not always so easy to archive. So you can use disableTimeToLive=true to not set a time to live value on the sent message. Then the message will not expire on the receiver system. See below in section About time to live for more details.
eagerLoadingOfProperties false Enables eager loading of JMS properties as soon as a message is received, which is generally inefficient, because the JMS properties might not be required. But this feature can sometimes catch early any issues with the underlying JMS provider and the use of JMS properties. This feature can also be used for testing purposes, to ensure JMS properties can be understood and handled correctly.
exceptionListener null Specifies the JMS Exception Listener that is to be notified of any underlying JMS exceptions.
errorHandler null Camel 2.8.2, 2.9: Specifies a org.springframework.util.ErrorHandler to be invoked in case of any uncaught exceptions thrown while processing a Message. By default these exceptions will be logged at the WARN level, if no errorHandler has been configured. From Camel 2.9.1: onwards you can configure logging level and whether stack traces should be logged using the below two options. This makes it much easier to configure, than having to code a custom errorHandler.
errorHandlerLoggingLevel WARN Camel 2.9.1: Allows to configure the default errorHandler logging level for logging uncaught exceptions.
errorHandlerLogStackTrace true Camel 2.9.1: Allows to control whether stacktraces should be logged or not, by the default errorHandler.
explicitQosEnabled false Set if the deliveryMode, priority or timeToLive qualities of service should be used when sending messages. This option is based on Spring's JmsTemplate. The deliveryMode, priority and timeToLive options are applied to the current endpoint. This contrasts with the preserveMessageQos option, which operates at message granularity, reading QoS properties exclusively from the Camel In message headers.
exposeListenerSession true Specifies whether the listener session should be exposed when consuming messages.
forceSendOriginalMessage false Camel 2.7: When using mapJmsMessage=false Camel will create a new JMS message to send to a new JMS destination if you touch the headers (get or set) during the route. Set this option to true to force Camel to send the original JMS message that was received.
idleTaskExecutionLimit 1 Specifies the limit for idle executions of a receive task, not having received any message within its execution. If this limit is reached, the task will shut down and leave receiving to other executing tasks (in the case of dynamic scheduling; see the maxConcurrentConsumers setting).
idleConsumerLimit 1 Camel 2.8.2, 2.9: Specify the limit for the number of consumers that are allowed to be idle at any given time.
jmsMessageType null Allows you to force the use of a specific javax.jms.Message implementation for sending JMS messages. Possible values are: Bytes, Map, Object, Stream, Text. By default, Camel would determine which JMS message type to use from the In body type. This option allows you to specify it.
jmsKeyFormatStrategy default

Pluggable strategy for encoding and decoding JMS keys so they can be compliant with the JMS specification. Camel provides two implementations out of the box: default and passthrough. The default strategy will safely marshal dots and hyphens (. and -). The passthrough strategy leaves the key as is. Can be used for JMS brokers which do not care whether JMS header keys contain illegal characters. You can provide your own implementation of the org.apache.camel.component.jms.JmsKeyFormatStrategy and refer to it using the # notation.

lazyCreateTransactionManager true If true, Camel will create a JmsTransactionManager, if there is no transactionManager injected when option transacted=true.
listenerConnectionFactory null The JMS connection factory used for consuming messages.
mapJmsMessage true Specifies whether Camel should auto map the received JMS message to an appropiate payload type, such as javax.jms.TextMessage to a String etc. See section about how mapping works below for more details.
maxMessagesPerTask -1 The number of messages per task. -1 is unlimited.
maximumBrowseSize -1 Limits the number of messages fetched at most, when browsing endpoints using Browse or JMX API.
messageConverter null To use a custom Spring org.springframework.jms.support.converter.MessageConverter so you can be 100% in control how to map to/from a javax.jms.Message.
messageIdEnabled true When sending, specifies whether message IDs should be added.
messageTimestampEnabled true Specifies whether timestamps should be enabled by default on sending messages.
password null The password for the connector factory.
priority 4 Values greater than 1 specify the message priority when sending (where 0 is the lowest priority and 9 is the highest). The explicitQosEnabled option must also be enabled in order for this option to have any effect.
pubSubNoLocal false Specifies whether to inhibit the delivery of messages published by its own connection.
receiveTimeout None The timeout for receiving messages (in milliseconds).
recoveryInterval 5000 Specifies the interval between recovery attempts, i.e. when a connection is being refreshed, in milliseconds. The default is 5000 ms, that is, 5 seconds.
replyToCacheLevelName - Camel 2.9.1: Sets the cache level by name for the reply consumer when doing request/reply over JMS. This option only applies when using fixed reply queues (not temporary). Camel will by default use: CACHE_CONSUMER for exclusive or shared w/ replyToSelectorName. And CACHE_SESSION for shared without replyToSelectorName. Some JMS brokers such as IBM WebSphere may require to set the replyToCacheLevelName=CACHE_NONE to work.
replyToDestinationSelectorName null Sets the JMS Selector using the fixed name to be used so you can filter out your own replies from the others when using a shared queue (that is, if you are not using a temporary reply queue).
replyToDeliveryPersistent true Specifies whether to use persistent delivery by default for replies.
requestTimeoutCheckerInterval 1000 Camel 2.9.2: Configures how often Camel should check for timed out Exchanges when doing request/reply over JMS.By default Camel checks once per second. But if you must react faster when a timeout occurs, then you can lower this interval, to check more frequently. The timeout is determined by the option requestTimeout.
subscriptionDurable false @deprecated: Enabled by default, if you specify a durableSubscriberName and a clientId.
taskExecutor null Allows you to specify a custom task executor for consuming messages.
taskExecutorSpring2 null Camel 2.6: To use when using Spring 2.x with Camel. Allows you to specify a custom task executor for consuming messages.
templateConnectionFactory null The JMS connection factory used for sending messages.
transactedInOut false @deprecated: Specifies whether to use transacted mode for sending messages using the InOut Exchange Pattern. Applies only to producer endpoints. See section Enabling Transacted Consumption for more details.
transactionManager null The Spring transaction manager to use.
transactionName "JmsConsumer[destinationName]" The name of the transaction to use.
transactionTimeout null The timeout value of the transaction, if using transacted mode.
transferException false If enabled and you are using Request Reply messaging (InOut) and an Exchange failed on the consumer side, then the caused Exception will be send back in response as a javax.jms.ObjectMessage. If the client is Camel, the returned Exception is rethrown. This allows you to use Camel JMS as a bridge in your routing - for example, using persistent queues to enable robust routing. Notice that if you also have transferExchange enabled, this option takes precedence. The caught exception is required to be serializable. The original Exception on the consumer side can be wrapped in an outer exception such as org.apache.camel.RuntimeCamelException when returned to the producer.
transferExchange false You can transfer the exchange over the wire instead of just the body and headers. The following fields are transferred: In body, Out body, Fault body, In headers, Out headers, Fault headers, exchange properties, exchange exception. This requires that the objects are serializable. Camel will exclude any non-serializable objects and log it at WARN level. You must enable this option on both the producer and consumer side, so Camel knows the payloads is an Exchange and not a regular payload.
username null The username for the connector factory.
useMessageIDAsCorrelationID false Specifies whether JMSMessageID should always be used as JMSCorrelationID for InOut messages.
useVersion102 false @deprecated (removed from Camel 2.5 onwards): Specifies whether the old JMS API should be used.

Message Mapping between JMS and Camel

Camel automatically maps messages between javax.jms.Message and org.apache.camel.Message.

When sending a JMS message, Camel converts the message body to the following JMS message types:

Body Type JMS Message Comment
String javax.jms.TextMessage
org.w3c.dom.Node javax.jms.TextMessage The DOM will be converted to String.
Map javax.jms.MapMessage
java.io.Serializable javax.jms.ObjectMessage
byte[] javax.jms.BytesMessage
java.io.File javax.jms.BytesMessage
java.io.Reader javax.jms.BytesMessage
java.io.InputStream javax.jms.BytesMessage
java.nio.ByteBuffer javax.jms.BytesMessage

When receiving a JMS message, Camel converts the JMS message to the following body type:

JMS Message Body Type
javax.jms.TextMessage String
javax.jms.BytesMessage byte[]
javax.jms.MapMessage Map<String, Object>
javax.jms.ObjectMessage Object

Disabling auto-mapping of JMS messages

You can use the mapJmsMessage option to disable the auto-mapping above. If disabled, Camel will not try to map the received JMS message, but instead uses it directly as the payload. This allows you to avoid the overhead of mapping and let Camel just pass through the JMS message. For instance, it even allows you to route javax.jms.ObjectMessage JMS messages with classes you do not have on the classpath.

Using a custom MessageConverter

You can use the messageConverter option to do the mapping yourself in a Spring org.springframework.jms.support.converter.MessageConverter class.

For example, in the route below we use a custom message converter when sending a message to the JMS order queue:

  from("file://inbox/order").to("jms:queue:order?messageConverter=#myMessageConverter");

You can also use a custom message converter when consuming from a JMS destination.

Controlling the mapping strategy selected

You can use the jmsMessageType option on the endpoint URL to force a specific message type for all messages.
In the route below, we poll files from a folder and send them as javax.jms.TextMessage as we have forced the JMS producer endpoint to use text messages:

  from("file://inbox/order").to("jms:queue:order?jmsMessageType=Text");

You can also specify the message type to use for each messabe by setting the header with the key CamelJmsMessageType. For example:

  from("file://inbox/order").setHeader("CamelJmsMessageType", JmsMessageType.Text).to("jms:queue:order");

The possible values are defined in the enum class, org.apache.camel.jms.JmsMessageType.

Message format when sending

The exchange that is sent over the JMS wire must conform to the JMS Message spec.

For the exchange.in.header the following rules apply for the header keys:

For the exchange.in.header, the following rules apply for the header values:

Camel will log with category org.apache.camel.component.jms.JmsBinding at DEBUG level if it drops a given header value. For example:

2008-07-09 06:43:04,046 [main           ] DEBUG JmsBinding  
  - Ignoring non primitive header: order of class: org.apache.camel.component.jms.issues.DummyOrder with value: DummyOrder{orderId=333, itemId=4444, quantity=2}

Message format when receiving

Camel adds the following properties to the Exchange when it receives a message:

Property Type Description
org.apache.camel.jms.replyDestination javax.jms.Destination The reply destination.

Camel adds the following JMS properties to the In message headers when it receives a JMS message:

Header Type Description
JMSCorrelationID String The JMS correlation ID.
JMSDeliveryMode int The JMS delivery mode.
JMSDestination javax.jms.Destination The JMS destination.
JMSExpiration long The JMS expiration.
JMSMessageID String The JMS unique message ID.
JMSPriority int The JMS priority (with 0 as the lowest priority and 9 as the highest).
JMSRedelivered boolean Is the JMS message redelivered.
JMSReplyTo javax.jms.Destination The JMS reply-to destination.
JMSTimestamp long The JMS timestamp.
JMSType String The JMS type.
JMSXGroupID String The JMS group ID.

As all the above information is standard JMS you can check the JMS documentation for further details.

About using Camel to send and receive messages and JMSReplyTo

The JMS component is complex and you have to pay close attention to how it works in some cases. So this is a short summary of some of the areas/pitfalls to look for.

When Camel sends a message using its JMSProducer, it checks the following conditions:

All this can be a tad complex to understand and configure to support your use case.

JmsProducer

The JmsProducer behaves as follows, depending on configuration:

Exchange Pattern Other options Description
InOut \- Camel will expect a reply, set a temporary JMSReplyTo, and after sending the message, it will start to listen for the reply message on the temporary queue.
InOut JMSReplyTo is set Camel will expect a reply and, after sending the message, it will start to listen for the reply message on the specified JMSReplyTo queue.
InOnly \- Camel will send the message and not expect a reply.
InOnly JMSReplyTo is set By default, Camel discards the JMSReplyTo destination and clears the JMSReplyTo header before sending the message. Camel then sends the message and does not expect a reply. Camel logs this in the log at WARN level (changed to DEBUG level from Camel 2.6 onwards. You can use preserveMessageQuo=true to instruct Camel to keep the JMSReplyTo. In all situations the JmsProducer does not expect any reply and thus continue after sending the message.

JmsConsumer

The JmsConsumer behaves as follows, depending on configuration:

Exchange Pattern Other options Description
InOut \- Camel will send the reply back to the JMSReplyTo queue.
InOnly \-

Camel will not send a reply back, as the pattern is InOnly.

So pay attention to the message exchange pattern set on your exchanges.

If you send a message to a JMS destination in the middle of your route you can specify the exchange pattern to use, see more at Request Reply.
This is useful if you want to send an InOnly message to a JMS topic:

from("activemq:queue:in")
   .to("bean:validateOrder")
   .to(ExchangePattern.InOnly, "activemq:topic:order")
   .to("bean:handleOrder");

Reuse endpoint and send to different destinations computed at runtime

If you need to send messages to a lot of different JMS destinations, it makes sense to reuse a JMS endpoint and specify the real destination in a message header. This allows Camel to reuse the same endpoint, but send to different destinations. This greatly reduces the number of endpoints created and economizes on memory and thread resources.

You can specify the destination in the following headers:

Header Type Description
CamelJmsDestination javax.jms.Destination A destination object.
CamelJmsDestinationName String The destination name.

For example, the following route shows how you can compute a destination at run time and use it to override the destination appearing in the JMS URL:

from("file://inbox")
  .to("bean:computeDestination")
  .to("activemq:queue:dummy");

The queue name, dummy, is just a placeholder. It must be provided as part of the JMS endpoint URL, but it will be ignored in this example.

In the computeDestination bean, specify the real destination by setting the CamelJmsDestinationName header as follows:

public void setJmsHeader(Exchange exchange) {
   String id = ....
   exchange.getIn().setHeader("CamelJmsDestinationName", "order:" + id");
}

Then Camel will read this header and use it as the destination instead of the one configured on the endpoint. So, in this example Camel sends the message to activemq:queue:order:2, assuming the id value was 2.

If both the CamelJmsDestination and the CamelJmsDestinationName headers are set, CamelJmsDestination takes priority.

Configuring different JMS providers

You can configure your JMS provider in Spring XML as follows:

  <camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
      <jmxAgent id="agent" disabled="true"/>
  </camelContext>

  <bean id="activemq" class="org.apache.activemq.camel.component.ActiveMQComponent">
    <property name="connectionFactory">
      <bean class="org.apache.activemq.ActiveMQConnectionFactory">
        <property name="brokerURL" value="vm://localhost?broker.persistent=false&roker.useJmx=false"/>
      </bean>
    </property>
  </bean>

Basically, you can configure as many JMS component instances as you wish and give them a unique name using the id attribute. The preceding example configures an activemq component. You could do the same to configure MQSeries, TibCo, BEA, Sonic and so on.

Once you have a named JMS component, you can then refer to endpoints within that component using URIs. For example for the component name, activemq, you can then refer to destinations using the URI format, activemq:[queue:|topic:]destinationName. You can use the same approach for all other JMS providers.

This works by the SpringCamelContext lazily fetching components from the spring context for the scheme name you use for Endpoint URIs and having the Component resolve the endpoint URIs.

Using JNDI to find the ConnectionFactory

If you are using a J2EE container, you might need to look up JNDI to find the JMS ConnectionFactory rather than use the usual <bean> mechanism in Spring. You can do this using Spring's factory bean or the new Spring XML namespace. For example:

<bean id="weblogic" class="org.apache.camel.component.jms.JmsComponent">
  <property name="connectionFactory" ref="myConnectionFactory"/>
</bean>

<jee:jndi-lookup id="myConnectionFactory" jndi-name="jms/connectionFactory"/>

See The jee schema in the Spring reference documentation for more details about JNDI lookup.

Concurrent Consuming

A common requirement with JMS is to consume messages concurrently in multiple threads in order to make an application more responsive. You can set the concurrentConsumers option to specify the number of threads servicing the JMS endpoint, as follows:

from("jms:SomeQueue?concurrentConsumers=20").
  bean(MyClass.class);

You can configure this option in one of the following ways:

Request-reply over JMS

Camel supports Request Reply over JMS. In essence the MEP of the Exchange should be InOut when you send a message to a JMS queue.
The JmsProducer detects the InOut and provides a JMSReplyTo header with the reply destination to be used. By default Camel uses a temporary queue, but you can use the replyTo option on the endpoint to specify a fixed reply queue (see more below about fixed reply queue).

Camel will automatic setup a consumer which listen on the reply queue, so you should not do anything.
This consumer is a Spring DefaultMessageListenerContainer which listen for replies. However it's fixed to 1 concurrent consumer.
That means replies will be processed in sequence as there are only 1 thread to process the replies. If you want to process replies faster, then we need to use concurrency. But not using the concurrentConsumer option. We should use the threads from the Camel DSL instead, as shown in the route below:

from(xxx)
.inOut().to("activemq:queue:foo")
.threads(5)
.to(yyy)
.to(zzz);

In this route we instruct Camel to route replies asynchronously using a thread pool with 5 threads.

Request-reply over JMS and using a shared fixed reply queue

If you use a fixed reply queue when doing Request Reply over JMS as shown in the example below, then pay attention.

from(xxx)
.inOut().to("activemq:queue:foo?replyTo=bar")
.to(yyy)

In this example the fixed reply queue named "bar" is used. By default Camel assumes the queue is shared when using fixed reply queues, and therefore it uses a JMSSelector to only pickup the expected reply messages (eg based on the JMSCorrelationID). See next section for exclusive fixed reply queues. That means its not as fast as temporary queues. You can speedup how often Camel will pull for reply messages using the receiveTimeout option. By default its 1000 millis. So to make it faster you can set it to 250 millis to pull 4 times per second as shown:

from(xxx)
.inOut().to("activemq:queue:foo?replyTo=bar&receiveTimeout=250")
.to(yyy)

Notice this will cause the Camel to send pull requests to the message broker more frequent, and thus require more network traffic.
It is generally recommended to use temporary queues if possible.

Request-reply over JMS and using an exclusive fixed reply queue

Available as of Camel 2.9

In the previous example, Camel would anticipate the fixed reply queue named "bar" was shared, and thus it uses a JMSSelector to only consume reply messages which it expects. However there is a drawback doing this as JMS selectos is slower. Also the consumer on the reply queue is slower to update with new JMS selector ids. In fact it only updates when the receiveTimeout option times out, which by default is 1 second. So in theory the reply messages could take up till about 1 sec to be detected. On the other hand if the fixed reply queue is exclusive to the Camel reply consumer, then we can avoid using the JMS selectors, and thus be more performant. In fact as fast as using temporary queues. So in Camel 2.9 onwards we introduced the ReplyToType option which you can configure to Exclusive
to tell Camel that the reply queue is exclusive as shown in the example below:

from(xxx)
.inOut().to("activemq:queue:foo?replyTo=bar&replyToType=Exclusive")
.to(yyy)

Mind that the queue must be exclusive to each and every endpoint. So if you have two routes, then they each need an unique reply queue as shown in the next example:

from(xxx)
.inOut().to("activemq:queue:foo?replyTo=bar&replyToType=Exclusive")
.to(yyy)

from(aaa)
.inOut().to("activemq:queue:order?replyTo=order.reply&replyToType=Exclusive")
.to(bbb)

The same applies if you run in a clustered environment. Then each node in the cluster must use an unique reply queue name. As otherwise each node in the cluster may pickup messages which was intended as a reply on another node. For clustered environments its recommended to use shared reply queues instead.

Synchronizing clocks between senders and receivers

When doing messaging between systems, its desirable that the systems have synchronized clocks. For example when sending a JMS message, then you can set a time to live value on the message. Then the receiver can inspect this value, and determine if the message is already expired, and thus drop the message instead of consume and process it. However this requires that both sender and receiver have synchronized clocks. If you are using ActiveMQ then you can use the timestamp plugin to synchronize clocks.

About time to live

Read first above about synchronized clocks.

When you do request/reply (InOut) over JMS with Camel then Camel uses a timeout on the sender side, which is default 20 seconds from the requestTimeout option. You can control this by setting a higher/lower value. However the time to live value is still set on the JMS message being send. So that requires the clocks to be synchronized between the systems. If they are not, then you may want to disable the time to live value being set. This is now possible using the disableTimeToLive option from Camel 2.8 onwards. So if you set this option to disableTimeToLive=true, then Camel does not set any time to live value when sending JMS messages. But the request timeout is still active. So for example if you do request/reply over JMS and have disabled time to live, then Camel will still use a timeout by 20 seconds (the requestTimeout option). That option can of course also be configured. So the two options requestTimeout and disableTimeToLive gives you fine grained control when doing request/reply.

When you do fire and forget (InOut) over JMS with Camel then Camel by default does not set any time to live value on the message. You can configure a value by using the timeToLive option. For example to indicate a 5 sec., you set timeToLive=5000. The option disableTimeToLive can be used to force disabling the time to live, also for InOnly messaging. The requestTimeout option is not being used for InOnly messaging.

Enabling Transacted Consumption

A common requirement is to consume from a queue in a transaction and then process the message using the Camel route. To do this, just ensure that you set the following properties on the component/endpoint:

See the Transactional Client EIP pattern for further details.

Transactions and [Request Reply] over JMS

When using Request Reply over JMS you cannot use a single transaction; JMS will not send any messages until a commit is performed, so the server side won't receive anything at all until the transaction commits. Therefore to use Request Reply you must commit a transaction after sending the request and then use a separate transaction for receiving the response.

To address this issue the JMS component uses different properties to specify transaction use for oneway messaging and request reply messaging:

The transacted property applies only to the InOnly message Exchange Pattern (MEP).

The transactedInOut property applies to the InOut(Request Reply) message Exchange Pattern (MEP).

If you want to use transactions for Request Reply(InOut MEP), you must set transactedInOut=true.

Available as of Camel 2.10

You can leverage the DMLC transacted session API using the following properties on component/endpoint:

The benefit of doing so is that the cacheLevel setting will be honored when using local transactions without a configured TransactionManager. When a TransactionManager is configured, no caching happens at DMLC level and its necessary to rely on a pooled connection factory. For more details about this kind of setup see here and here.

Using JMSReplyTo for late replies

When using Camel as a JMS listener, it sets an Exchange property with the value of the ReplyTo javax.jms.Destination object, having the key ReplyTo. You can obtain this Destination as follows:

Destination replyDestination = exchange.getIn().getHeader(JmsConstants.JMS_REPLY_DESTINATION, Destination.class);

And then later use it to send a reply using regular JMS or Camel.

    // we need to pass in the JMS component, and in this sample we use ActiveMQ
    JmsEndpoint endpoint = JmsEndpoint.newInstance(replyDestination, activeMQComponent);
    // now we have the endpoint we can use regular Camel API to send a message to it
    template.sendBody(endpoint, "Here is the late reply.");

A different solution to sending a reply is to provide the replyDestination object in the same Exchange property when sending. Camel will then pick up this property and use it for the real destination. The endpoint URI must include a dummy destination, however. For example:

    // we pretend to send it to some non existing dummy queue
    template.send("activemq:queue:dummy, new Processor() {
        public void process(Exchange exchange) throws Exception {
            // and here we override the destination with the ReplyTo destination object so the message is sent to there instead of dummy
            exchange.getIn().setHeader(JmsConstants.JMS_DESTINATION, replyDestination);
            exchange.getIn().setBody("Here is the late reply.");
        }
    }

Using a request timeout

In the sample below we send a Request Reply style message Exchange (we use the requestBody method = InOut) to the slow queue for further processing in Camel and we wait for a return reply:

        // send a in-out with a timeout for 5 sec
        Object out = template.requestBody("activemq:queue:slow?requestTimeout=5000", "Hello World");

Samples

JMS is used in many examples for other components as well. But we provide a few samples below to get started.

Receiving from JMS

In the following sample we configure a route that receives JMS messages and routes the message to a POJO:

   from("jms:queue:foo").
     to("bean:myBusinessLogic");

You can of course use any of the EIP patterns so the route can be context based. For example, here's how to filter an order topic for the big spenders:

from("jms:topic:OrdersTopic").
  filter().method("myBean", "isGoldCustomer").
    to("jms:queue:BigSpendersQueue");

Sending to a JMS

In the sample below we poll a file folder and send the file content to a JMS topic. As we want the content of the file as a TextMessage instead of a BytesMessage, we need to convert the body to a String:

from("file://orders").
  convertBodyTo(String.class).
  to("jms:topic:OrdersTopic");

Using Annotations

Camel also has annotations so you can use POJO Consuming and POJO Producing.

Spring DSL sample

The preceding examples use the Java DSL. Camel also supports Spring XML DSL. Here is the big spender sample using Spring DSL:

<route>
  <from uri="jms:topic:OrdersTopic"/>
  <filter>
    <method bean="myBean" method="isGoldCustomer"/>
    <to uri="jms:queue:BigSpendersQueue"/>
  </filter>
</route>

Other samples

JMS appears in many of the examples for other components and EIP patterns, as well in this Camel documentation. So feel free to browse the documentation. If you have time, check out the this tutorial that uses JMS but focuses on how well Spring Remoting and Camel works together Tutorial-JmsRemoting.

Using JMS as a Dead Letter Queue storing Exchange

Normally, when using JMS as the transport, it only transfers the body and headers as the payload. If you want to use JMS with a Dead Letter Channel, using a JMS queue as the Dead Letter Queue, then normally the caused Exception is not stored in the JMS message. You can, however, use the transferExchange option on the JMS dead letter queue to instruct Camel to store the entire Exchange in the queue as a javax.jms.ObjectMessage that holds a org.apache.camel.impl.DefaultExchangeHolder. This allows you to consume from the Dead Letter Queue and retrieve the caused exception from the Exchange property with the key Exchange.EXCEPTION_CAUGHT. The demo below illustrates this:

// setup error handler to use JMS as queue and store the entire Exchange
errorHandler(deadLetterChannel("jms:queue:dead?transferExchange=true"));

Then you can consume from the JMS queue and analyze the problem:

from("jms:queue:dead").to("bean:myErrorAnalyzer");

// and in our bean
String body = exchange.getIn().getBody();
Exception cause = exchange.getProperty(Exchange.EXCEPTION_CAUGHT, Exception.class);
// the cause message is
String problem = cause.getMessage();

Using JMS as a Dead Letter Channel storing error only

You can use JMS to store the cause error message or to store a custom body, which you can initialize yourself. The following example uses the Message Translator EIP to do a transformation on the failed exchange before it is moved to the JMS dead letter queue:

// we sent it to a seda dead queue first
errorHandler(deadLetterChannel("seda:dead"));

// and on the seda dead queue we can do the custom transformation before its sent to the JMS queue
from("seda:dead").transform(exceptionMessage()).to("jms:queue:dead");

Here we only store the original cause error message in the transform. You can, however, use any Expression to send whatever you like. For example, you can invoke a method on a Bean or use a custom processor.

Sending an InOnly message and keeping the JMSReplyTo header

When sending to a JMS destination using camel-jms the producer will use the MEP to detect if its InOnly or InOut messaging. However there can be times where you want to send an InOnly message but keeping the JMSReplyTo header. To do so you have to instruct Camel to keep it, otherwise the JMSReplyTo header will be dropped.

For example to send an InOnly message to the foo queue, but with a JMSReplyTo with bar queue you can do as follows:

        template.send("activemq:queue:foo?preserveMessageQos=true", new Processor() {
            public void process(Exchange exchange) throws Exception {
                exchange.getIn().setBody("World");
                exchange.getIn().setHeader("JMSReplyTo", "bar");
            }
        });

Notice we use preserveMessageQos=true to instruct Camel to keep the JMSReplyTo header.

Setting JMS provider options on the destination

Some JMS providers, like IBM's WebSphere MQ need options to be set on the JMS destination. For example, you may need to specify the targetClient option. Since targetClient is a WebSphere MQ option and not a Camel URI option, you need to set that on the JMS destination name like so:

...
.setHeader("CamelJmsDestinationName", constant("queue:///MY_QUEUE?targetClient=1"))
.to("wmq:queue:MY_QUEUE?useMessageIDAsCorrelationID=true");

Some versions of WMQ won't accept this option on the destination name and you will get an exception like:

com.ibm.msg.client.jms.DetailedJMSException: JMSCC0005: The specified value 'MY_QUEUE?targetClient=1' is not allowed for 'XMSC_DESTINATION_NAME'

A workaround is to use a custom DestinationResolver:

JmsComponent wmq = new JmsComponent(connectionFactory); 
        
wmq.setDestinationResolver(new DestinationResolver(){ 
    public Destination resolveDestinationName(Session session, String destinationName, boolean pubSubDomain) throws JMSException { 
        MQQueueSession wmqSession = (MQQueueSession) session;	
        return wmqSession.createQueue("queue:///" + destinationName + "?targetClient=1"); 
    }        
}); 

See Also