I have a web-app with some JARs in WEB-INF/lib. I put them there for using the web-app run/debug feature. While running the web-app, the JARs are blocked (i.e. I cannot delete or update them) which ist fine since the server needs them. Usually after stopping the server the JARs are freed (i.e. I can delete or update them), but sometimes the JARs remain blocked and I cannot update them for the next run. Is there any known reason for the JARs remaining blocked sometimes after stopping the web-app?