Nima Kaviani wrote: > I have developed a cross platform bundle that installs/uninstalls either > comm-win32 or comm-linux jars to enable communication with the serial port. > Everything works fine on Linux, however on windows, Felix seems to cache > win32com.dll along with other files and folders at the time of installing > comm-win32 but then it is unable to remove win32com.dll when comm-win32 gets > uninstalled.
This is a common problem especially on Windows. You still have outstanding references from your code to the bundle class loader; this prevents the class loader from being GC'ed on bundle uninstall. Since the classloader keeps a reference to the native library and only clears it when it itself is finalized, the library cannot be deleted since Windows does not allow deletion of open files. It is likely that the same happens on Linux - you just have not noticed it since open files can be deleted on Linux. Whether that is a bug or feature is..debatable. The fix is simple: make sure you do not keep any references. :) Good candidates are static singletons or other class references, especially when they have escaped from the bundle and are kept alive outside. > As a consequence, the next time I bring up the framework, there > is a partially corrupted folder in the felix cache corresponding to the > presumably removed comm-win32 bundle which causes the following exception at > the time of starting the framework. Everything gets back to normal as soon > as I delete the corrupted bundle folder from the cache. The behavior happens > both with Felix 1.8.0 and 2.0.0. Yup, common problem - I observed the same. See discussion here: http://www.mail-archive.com/[email protected]/msg05211.html Equinox is a bit more forgiving as it swallows the exception and puts the "zombie" bundle cache on a blacklist that is deleted on the next start. Whether that is better or not is again debatable; I think a zombie bundle hogs the native library entry and prevents reloading a library with the same name. If your bundle has the same lifecycle as the framework/JVM then this should not be a problem. > I wonder if there is a way to force Felix to remove the cached folder for > this bundle (along with the dll file)? or is there anything that I am not > doing properly at the time of uninstalling comm-win32 which somehow does not > release win32com.dll when it comes to cleaning the cache? See above. There *is* a way to make the classloader give up the reference and let go of the native library, but it is evil and could kills kittens or even bring a certain Dr. Watson to the crime scene. If you really want to have it, send me an email. :) Holger --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
