How to check that a plugin has properly unloaded completely?

Hi,

We’‘re running into an reoccurring problem while developing Openfire plugins: Whenever a plugin doesn’‘t destroy properly (which happens when destroyPlugin throws an Exception, for example, or when destroyPlugin doesn’'t close all references that the plugin holds), you will end up with a half-loaded plugin. All kinds of unexpected behavior might occur as a result, especially if you then reload the plugin.

Is there a way to check that plugins unload completely, preferably one that can be checked programmatically?