Caught exception inaccessible after routing - jboss

Question

I'm building an exception handler for a jboss/camel project. Catching the exception with an onException clause works, and I can access the caught exception from a bean, but that work's only directly in exception handler. Since I need this handler in multiple different projects, I want to direct from the handler to a different route (in a different context), and handle the exception there centrally. But after the routing, the caught exception is not accessible any longer. Why is this, and how can I fix that. I'd like not to have to add another EJB to all of my projects.
Code:
<camelContext id="project1Context" xmlns="http://camel.apache.org/schema/spring">
<onException>
<exception>java.lang.Exception</exception>
<handled>
<constant>true</constant>
</handled>
<bean ref="projectSpecificBean" method="peekException" />
<to uri="activemq:queue:centralExceptionHandling" />
</onException>
[... the routes of the context, where the exception happens ...]
</camelContext>
In the bean:
public void peekException(Exchange camelExchange) {
Exception e = camelExchange.getProperty(Exchange.EXCEPTION_CAUGHT, Exception.class);
log.warn("Caught general Exception", e);
}
This gives me access to the Exception inside the bean. But when I remove the <bean ref="projectSpecificBean" method="peekException" /> from the onException clause and add the same thing to the route at activemq:queue:centralExceptionHandling (to a bean local to that project there, in a different camelContext), I cannot find the exception anywhere in the exchange.

Answer 1

To be able to receive exception on the client of ActiveMQ queue you need use camel jms component option "transferExchange". This option must be enabled on both sides (during sending to ActiveMQ queue and receiving from it). In that case not only message body/headers will be sent but whole exchange will be transfered. See http://camel.apache.org/jms.html (transferExchange option). In general it will then looks like there are no queue between exception route and exception handler route. Here are some details from documentation:
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.
Example of code:
<camelContext id="project1Context" xmlns="http://camel.apache.org/schema/spring">
<onException>
<exception>java.lang.Exception</exception>
<handled>
<constant>true</constant>
</handled>
<bean ref="projectSpecificBean" method="peekException" />
<to uri="activemq:queue:centralExceptionHandling?transferExchange=true" />
</onException>
[... the routes of the context, where the exception happens ...]
</camelContext>
// Somewhere in the central exception handler.
<camelContext id="exceptionHandlerContext" xmlns="http://camel.apache.org/schema/spring">
<route>
<from uri="activemq:queue:centralExceptionHandling?transferExchange=true" />
<!-- Here you will have almost completely the same exchange as it was before it was sent to ActiveMq -->
</route>
</camelContext>