Question

I’m using log4j for my logging purposes. To configure everything, I’ve made a log4j.xml that is outside of the jar-file. It works great, but gives problems when the jar-file isn’t executed from the same directory where the log4j.xml is.

Example: jar-file is in /opt/myapp/test.jar

user@host:/opt/myapp$ java -jar test.jar

works great, but when I try this:

user@host:~$ java -jar /opt/myapp/test.jar

I get an error that log4j.xml cannot be found. That’s because it is looking for it in my current working directory.

I also have a properties file that I use in my application. This file is in the config/ directory where the jar-file is, so /opt/myapp/config in this example. The same issue like the one above occurs when trying to load the config file.

How can I let Java load a file from the directory where the jar-file is (no matter from where the jar is executed)?

Probably something very easy, but I can’t figure it out 🙁

Answer 1

1. Specify using log4j system property, add this before that “-jar” part of the command:
   -Dlog4j.configuration=/opt/myapp/log4j.xml

2. Add the directory to the classpath, add this before that “-jar” part of the command:

   -cp /opt/myapp/

3. You can specify the log4j.xml file manually in code and then reference it relative your jar file.

   • Do something like this to find the file:
     Fetch file from specific directory where jar file is placed
   • And to configure log4j:

   String path = … ;
   PropertyConfigurator.configure(path);