This setting defines where the logs will be written to. There are three predefined values:
stdout: Standard output
stderr: Standard error
slf4j: Force using the SLF4J logging framework
The default behavior is: Try to use slf4j if it seems to be usable (i.e. if the corresponding classes exist), otherwise fall back to stdout.
Finally, if the setting does not correspond to any of the predefined values (as shown in the example above), the value is interpreted as a filename.
It is strongly recommended to provide an absolute path. Also ensure that the target directory exists, and that the file can be written to.
If logging to the given file fails for some reason, it will fall back to the default as specified above.