Mule: getting a hold of the exception message

Question

I have a default catch exception in Mule, and I'm trying to get access to the exception message, using a Mule expression: #[exception]

This doesn't seem to work, and I'm guessing that I'm trying to access the wrong variable? I'm trying to log it using logger and also run a custom component that takes in an exception message (as a string.)

Thanks,

Answer 1

You can do #[exception.causedBy] like

   <choice-exception-strategy>
        <catch-exception-strategy when="exception.causedBy(com.company.BusinessException)"> <!-- [1] -->
            <jms:outbound-endpoint queue="dead.letter">
                <jms:transaction action="ALWAYS_JOIN" />
            </jms:outbound-endpoint>
        </catch-exception-strategy>
        <rollback-exception-strategy when="exception.causedBy(com.company.NonBusinessException)"> <!-- [2] -->
            <logger level="ERROR" message="Payload failing: #[payload]"/>
        </rollback-exception-strategy>
    </choice-exception-strategy>

More details here

Answer 2

In some cases the exception.cause could be null, hence advised to use the conditional to display the message:

[(exception.cause!=null)?(exception.cause.message):exception]

This will prevent null pointer exception.

Answer 3

Best way to get exception message (null safe) is :

#[exception.cause.?message or exception.cause]

Answer 4

Hi if you want to get the exception message using MEL you can also (in a Catch Exception Strategy) use the following expression.

#[exception.cause.message]

Answer 5

exception.cause could be null so it could be handled like this:

#[exception.?cause.message or exception]