Hi, NB: I am not the maintainer of sun-java6.
I think sun-java6 can be autobuilt; I checked it's copyright file and didn't find anything discouraging autobuilding. I intend to NMU the package to add the "XS-Autobuild: yes" field as described in: http://lists.debian.org/debian-devel-announce/2006/11/msg00012.html and a note in debian/copyright. Bye, -- Loïc Minier