This collaboration (coopetition?) is not new for GlassFish given Oracle’s contribution of TopLink, TmaxSoft’s use of GlassFish for its JEUS product, JBoss’ use of JAXB and JSF and Jetty’s use of Grizzly. Note that most of these technologies are available thru Maven.
Also, Shai is giving GlassFish another try and finding some major improvements which he things are Open-Source related. He also complains about error messages which are an ongoing task in the GlassFish community (the problem has been reported several times). Not an easy task.