Question

Suppose I want to reflect exception in the log.

Should I pass stack trace into log.error() or just Exception’s toString()? Or do something better?

How to obtain stack trace string to pass to logger?

Answer 1

All modern logging frameworks treat passed Exception object special:

log.error("Danger! High Voltage!", ex);

The framework (let it be logback or log4j) will format the stack trace nicely for you. Always log the full stack trace unless you really know what you are doing. Otherwise you can always filter out exceptions from given logger.

Also note that many important exception do not provide meaningful message, NullPointerException being important example.