Parameterized Info intermittently throws IllegalArgumentException

[arbardhan]

I log 8 parameters using {} in log.info this comes from a httpServlet request preHandlePath. This log statement sometimes throwa IAE exception stating only 5 arguments provided for 8 placeholders.

I do evaluate some expressions onFly. Tried dumping them as String in a variable and then print - no luck.

Using 2.23.1

[ppkarwasz]

@arbardhan,

Did you test with the latest release (2.24.3)?

[arbardhan]

2.24.3 is not available under our org enterprise distribution yet - pending approval. We only go back to older versions. But can you think of scenarios where this may occur ?

[ppkarwasz]

But can you think of scenarios where this may occur ?

In version 2.21.0, the parameter formatting logic was changed to strictly enforce a match between {} placeholders and arguments—throwing an exception on mismatch. This broke backward compatibility. The original lenient behavior was restored in version 2.24.0 (see #2380).

As for the cause of the mismatch: could you share your logging statement and the API you're using? The Log4j API supports up to 10 arguments before switching to varargs, while others switch to varargs much sooner. I suspect that varargs arguments might be trimmed by some logging bridge.

2.24.3 is not available under our org enterprise distribution yet - pending approval.

Could you share more about your upgrade policy? I’m currently working with the non-profit Open Source Economy to explore the feasibility of supporting multiple minor Log4j versions simultaneously. Right now, all Log4j maintainers are volunteers, so we can only support the latest version. However, with funding from OSE’s clients, we could potentially take on broader Log4j maintenance as part of our regular work.