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,

After some time I figured out that my issue was due to nesting #[] where they shouldn't have been nested. However I still have an issue, #[exception] will return the Mule top error, which isn't very interesting in what really happened. I'm just getting invoking a component failed, while the real error I want to output is the root error (permission denied on a directory creation from sftp.) Any way to get the root error message from the #[exception] object? — Loic Duros, Apr 28 '14 at 14:39

score 9 · Answer 1 · edited Jul 06 '15 at 01:05

9

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.

edited Jul 06 '15 at 01:05

FormigaNinja

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answered Jul 06 '15 at 00:01

Prathiba

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score 9 · Answer 2 · answered Aug 31 '16 at 05:58

9

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

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

answered Aug 31 '16 at 05:58

Nirmal- thInk beYond

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Hi @Nirmal- thInk beYond. What is the question mark for in your answer? What does it do? Thanks! ---Edit--- Never mind! I just found the answer here. https://docs.mulesoft.com/mule-user-guide/v/3.8/mule-expression-language-tips Thanks! – Hoonerbean Mar 15 '17 at 20:04
@Rashiki the question mark is a check for a null pointer exception. – granthbr Mar 31 '17 at 13:36

score 4 · Accepted Answer · answered Apr 28 '14 at 14:57

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

score 3 · Answer 4 · answered Oct 09 '14 at 06:40

3

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]

answered Oct 09 '14 at 06:40

Nicolas

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score 1 · Answer 5 · answered Jun 13 '17 at 06:53

1

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

#[exception.?cause.message or exception]

answered Jun 13 '17 at 06:53

pulsar

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Mule: getting a hold of the exception message

5 Answers5