title: Using system environment variables in log4j xml configuration
body: <p>Is it possible to reference system environment variables (as opposed to Java system properties) in a log4j xml configuration file?</p>
  
  <p>I'd like to be able to do something like:</p>
  
  <pre><code>&lt;level value="${env.LOG_LEVEL}" /&gt;
  </code></pre>
  
  <p>and have it get that from the system environment variables, so I can avoid having to pass in so many things with -D parameters.</p>