Use FileLocator.toFileURL()
on the URL
returned by FileLocator.resolve()
to get a more normal URL.
Note: this will expand your jar in to a temporary cache so that a normal file URL can be returned. This cache is not guaranteed to be persistent so if you want database changes to persist you need to put the database somewhere else.
One possibility is to copy the database to the workspace .metadata in the plugin state data (see Platform.getStateLocation(bundle)
.