The SUNW?cfg package was required to do 3 things:
see PSARC document:
http://psarc.us.oracle.com/PSARC/2003/091/spec

1. install the prefs default directory
2. install the javaws linkages
3. install file association for javaws

As of the fix for JDK-8023288, deployment linking and association is no longer needed
and was removed with JDK-8023498, the only function of the above package
is the prefs directory, the need of this should be clarified with the core-libs
team likely on core-libs-dev and this package should be removed, when
convenient.