Hi LogBack-Team, just want to tell you that MDC lacks thread support. But I'm quite sure that you know that. As soon as you "leave" a thread the MDC conext (ThreadLocal) will be lost. I had implemented something similar to MDC a while ago and I accompanied my impl with a ContextPreservingRunnable after a while. Works like this CTOR (Source Thread): ContextPreservingRunnable(Runnable inSubject) { myMemento = MDC.getMemento(); mySubject = inSubject; } RUN-Method (Target Thread): void run() { MDC.setMemento(myMemento); mySubject.run(); MDC.clear(); } Even though it works for me, it's rather bad that you have to wrap all Runnables and Callables respectively. Maybe a ExecutorFacade might server the purpose? BTW: Does MDC include support for a Subjects Principals (JAAS)...Please forgive me my showing off at dev list;-) __________________________________ Yahoo! Clever - Der einfachste Weg, Fragen zu stellen und Wissenswertes mit Anderen zu teilen. www.yahoo.de/clever