How to log exception and message with placeholders with SLF4J

Question

What's the correct approach to log both an error message and an exception using SLF4J?

I've tried doing this but the exception stack trace is never printed:

logger.error("Unable to parse data {}", inputMessage, e);

In this case I want to populate {} with the inputMessage as well as logging out the exception stacktrace.

The only way I can see to do this would be to do this:

logger.error("Unable to parse data " + inputMessage, e);

which is not pretty.

Answer 1

As of SLF4J version 1.6, SLF4J will interpret the last parameter as you intended, i.e. as an exception. You must be using an older version of SLF4J API.

This feature is documented in a faq entry which is also referenced in the javadocs for Logger.