Hi, Have some weired idea and would like to hear if someone already faced something similar. It's not directly related neither to AS nor Tomcat but both of them have the conceptually similar application classloaders where you put some component .jar in some (usually) lib/ folder and it gets loaded and hopefully unloaded on undeployment. Now, the handy feature I need would be similar to Operating System "Move on reboot" or "Reboot required" functionality. In essence, like with some native installations there are two major issues. Depending on what you are installing it might just go on, or it might require OS reboot. Installation might just be done for current user or it might require elevated security. So the first thing, if for example, my .war or .ear needs to install something to core AS or to the catalina.home/ext is the option to tell the deployer to unpack something in a different location, and mark the "OS" (in this case my container) to reboot. This requires delegating this to the parent classloader or even to the sun.misc.Launcher$ExtClassLoader The second thing is undeployment or uninstall where some part of what was installed can be physically deleted only on reboot (probably either by some cleanup task on shutdown or by some cleanup on startup) This probably breaks a whole bunch of specs and has potential security implications, but given "admin" security credentials it can be done without impacting "user" security. Dunno how Adrian did it for MC, but I suppose it just sweeps trough some given .jar list on deployment and loads those classes. My idea was to write down the generic .jar pre-loader that would get loaded instead real .jar, figure out the required parent classloader, use own action mechanism for physical deployment (unpacking native libraries from .jar for example) and do an actual classloading. On undeploy pre-loader would get notified (dunno how yet) and install shutdown hook so that everything gets cleaned up "on reboot". Next thing are partial deployments, where pre-loader would need to figure out if the previous package is already installed (redeployment without reboot) in which case the versioning of the components would either allow to continue doing nothing or refuse to load until reboot is done. The second is common behavior now if a package contains native library references cause they are all referenced in system classloader regardless of actual classloader used (and that is what I wish to resolve basically; packing java and native code inside archive and make everything plug-and-play). There is Java Module API JSR-227 (for Java7 thought) and it defines the native libraries as resource concept, but since (according to the spec) it'll forward the System.loadLibrary() to the defining class loader of the calling class the issue will still remain. Does this make any sense? Need some theory on how for example I could write a code that would get notified when my .jar get loaded and unloaded by defining classloader. Since there's no module classloading API (has to be generic) I can use (eg. a simple URLClassLoader) I suppose I'll need some voodoo for that :) Regards -- ^(TM)