Hi, I have been trying to setup a property 'applicationUrl' which can be evaluated at runtime. I have created the PropertyConfigurer as below: public class LogbackApplicationURLPropertyDefiner extends PropertyDefinerBase { public String getPropertyValue() { LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory(); lc.putProperty(); return ( UserContext.getUserContext() == null ? "User context was null, application url could not be determined" : UserContext.getUserContext().getApplicationUrl() ); } } and in the xml as: <define name="applicationUrl" class="com.iblogix.analytic.logging.LogbackApplicationURLPropertyDefiner"/> But it looks like the value is evaluated only once during the logback configruation. What I want is that the value be evaluated everytime it is acessed by someone. Is that possible using what i have right now? Thanks, Basu