JRuby middleman server on windows

I’m trying to run middleman as server from JRuby, as part of my Java project components to build the project UI. The thing is that when adding the wdm watching dependency on JRuby, to watch files on Windows, it fails to add that gem because of:

NotImplementedError: C extension support is not enabled. Pass -Xcext.enabled=true to JRuby or set JRUBY_OPTS.

If I don’t add the wdm gem, then middleman servers starts, but is not aware of file changes on my computer, therefore there is no watching.

What can I do? Please help