[LOG4J2-3243] Property log4j.configurationFile incorrectly documented, log4j.configuration missing

• Type: Documentation
• Status: Resolved
• Priority: Minor
• Resolution: Cannot Reproduce
• Affects Version/s: 2.16.0
• Component/s: Configuration
• Assignee: Unassigned
• Reporter: Sascha Volkenandt
• Created: 16/Dec/21 13:33
• Updated: 17/Feb/22 23:43
• Resolved: 17/Feb/22 23:43

Description

According to [1], Log4j looks for the system property log4j2.configurationFile. According to the sources of log4j-core-2.16.0 (ConfigurationFactory.java), the searched property is log4j.configurationFile. The other property does not seem to have any effect in recent versions.

[1] https://logging.apache.org/log4j/2.x/manual/configuration.html

Additionally, since 2.14.0 it looks for the property log4j.configuration (no "File"), which was also the property used by Log4j 1.x. As a consequence, logging stopped working in some of our systems after upgrading to 2.16.0 due to Log4Shell. Those systems are using both 1.x and 2.x so they have the property log4j.configuration set but not log4j.configurationFile, because we relied on the previous behaviour that if log4j.configurationFile is not set it looks in the classpath. I had to use a debugger to find out why it stopped working.

It would be nice if that second property would also be mentioned in [1].