Mule Request Reply and Rollback Exception Strategy - mule

Question

I've a mule flow where I configured Request Reply scope. The flow is like below:
<flow name="RequestReplyFlow">
<http:listener config-ref="HTTP_Listener_Configuration" path="/test" doc:name="HTTP" />
<set-payload value="#['Sample Payload']" doc:name="Set Payload" />
<request-reply doc:name="Request-Reply">
<vm:outbound-endpoint exchange-pattern="one-way" path="request" doc:name="VM" />
<vm:inbound-endpoint exchange-pattern="one-way" path="reply" doc:name="VM" />
</request-reply>
</flow>
and
<flow name="RequestReplyFlow1">
<vm:inbound-endpoint exchange-pattern="one-way" path="request" doc:name="VM" />
<logger message="Executing with payload: #[payload]" level="INFO" doc:name="Logger" />
<component class="org.ram.BusinessComponent" doc:name="Java" />
<rollback-exception-strategy maxRedeliveryAttempts="5" doc:name="Rollback Exception Strategy">
<logger message="Will attempt redelivery" level="INFO" doc:name="Logger" />
</rollback-exception-strategy>
</flow>
I configure rollback-exception-strategy on the request VM inbound endpoint.
When the component org.ram.BusinessComponent throws an exception, what I expected is the message is redelivered to the inbound VM endpoint but it did not happen. Why?
Can anyone please solve the issue?

Answer 1

If you are using rollback exception strategy instead of default exception strategy for unhandled exceptions, then you just have to specify the redirection manually in the "rollback-exception-strategy" by adding the "vm:outbound-endpoint" with the "reply" path, note that the maxRedeliveryAttempts was changed to "0" because your vm is not transactional:
<flow name="RequestReplyFlow1">
<vm:inbound-endpoint exchange-pattern="one-way" path="request" doc:name="VM" />
<logger message="Executing with payload: #[payload]" level="INFO" doc:name="Logger" />
<component class="org.ram.BusinessComponent" doc:name="Java" />
<rollback-exception-strategy maxRedeliveryAttempts="0" doc:name="Rollback Exception Strategy">
<logger message="Will attempt redelivery" level="INFO" doc:name="Logger" />
<vm:outbound-endpoint exchange-pattern="one-way" path="reply" doc:name="VM" />
</rollback-exception-strategy>
</flow>
When the vm is transactional then the value maxRedeliveryAttempts=5 makes sense because in that case Mule attempts message redelivery five (5) times. Then you can specify the redirection manually in the "rollback-exception-strategy" by adding the "vm:outbound-endpoint" with the "reply" path inside the "on-redelivery-attempts-exceeded" child element:
<flow name="RequestReplyFlow1">
<vm:inbound-endpoint exchange-pattern="one-way" path="request" doc:name="VM" />
<logger message="Executing with payload: #[payload]" level="INFO" doc:name="Logger" />
<component class="org.ram.BusinessComponent" doc:name="Java" />
<rollback-exception-strategy maxRedeliveryAttempts="0" doc:name="Rollback Exception Strategy">
<logger message="Will attempt redelivery" level="INFO" doc:name="Logger" />
<on-redelivery-attempts-exceeded>
<logger message="redelivery attempt exceeded" level="INFO" doc:name="Logger" />
<vm:outbound-endpoint exchange-pattern="one-way" path="reply" doc:name="VM" />
</on-redelivery-attempts-exceeded>
</rollback-exception-strategy>
</flow>