Apple started in 2006 with no deal or coordination with Sun. Later when the FUD started, they were looking for protection from patent lawsuits (i.e. from NetApp

Apple started in 2006 with no deal or coordination with Sun. Later when the FUD started, they were looking for protection from patent lawsuits (i.e. from NetApp), for support and expertise, and, possibly, reassurances around patent clauses within the CDDL with which I'm not an expert.