changing a dependent jdk port out for an equivalent one

[Gary Aitken]

I've got diablo-jdk installed, and it is deprecated.
openjdk6 and openjdk7 should be substitutable for diablo-jdk.

Is there a way to swap the one out for the other?
e.g.
  portmaster -e java/diablo-jdk
  portmaster java/openjdk7
and then a miracle occurs...

I see in the ant makefile that run_depends is on java/jvmwrapper,
which might somehow make that work.

Gary