If you are using a Tomcat server that is started with server.startup.bat:
The location of the log files is determined by the log4j.properties file in the [xxx Install Dir]/server/conf/jazz directory. You can define the location of the log4j.properties with the JVM argument Dlog4j.configuration=<full file path>.
If you are using Tomcat, the JVM arguments are set in the server.startup script from the command line. If you are using WebSphere Application Server, the JVM arguments are set in the WebSphere Application Server JVM configuration page.
The default setting for thexxx.log is log4j.appender.logfile.File=xxx.log. The default setting for jazz.log is log4j.appender.file.File=tomcat/logs/jazz.log.