title: spring boot log4j file external to jar?
body: <p>how to pass? The only way I can get this to work is to put log4j.xml on the classpath. </p>
  
  <p>passing: -Dlog4j.configuration=file:///c:\log4j2.xml on the command line doesn't work (although it does in a non spring-boot test application just fine).</p>
  
  <p>I also tried putting this as an environment variable/property in spring.</p>