log4j.properties not picked up from jar

Question

I have a jar in the classpath of my server which contains the log4j.properties file on root of the jar for logging of the code. When the code in the jar runs the logging for the code is not occuring. When I analyzed the problem using java -Dlog4j.debug option I got to know that the log4j is loading the log4j.properties file of axis-ant.jar (this also is on my classpath) and using it instead of my jar's property file.

When i subsequently removed the axis-ant.jar from the classpath my jars log4j.properties file was picked immediately and logging for my code occured.

Can somebody please explain why is my log4j.properties fle not being loaded while axis-ant.jar is present?

Surprisingly the same jar with axis-ant.jar present in classpath is running with proper logging successfully in another server.. both the server have the same java 5 version installed and same version of log4j jar

Answer 1

You should have a look at the log4j manual. The section "Default Initialization Procedure" describes how log4j will try to find the initialization file and explains possibilities to match a special configuration (e.g. by setting the system property log4j.configuration).

If you do not want to do any special configuration you have to ensure that your configuration file will be the first one found on the classpath.

Answer 2

The properties file is picked up from the jar based on the order in which the jar is found in classpath by your application server. Now there is no way to conclusively tell the jar from which the properties file is to be loaded.

To get around this problem most projects include your log4j.properties file in the server classpath itself. This way this file is the first properties file to be loaded and this is the one which your logging code gets.