It has been pointed out to me that Oracle is ending public support for Java 1.6 around November 2012 () and so many of our users will be looking to move to Java 7 in that timeframe.
Bug 382688 is the only remaining issue in running Virgo 3.5.0 on Java 7. My guess is that we'll have to weaken the test to accommodate the change in behaviour in Java 7. But the net is that we haven't yet switched to Java 7 for development or testing.
I had a disappointing experience when I tried switching to Java 7 on Mac OS X in that Eclipse (Indigo) became unstable. Perhaps Juno is better, although I haven't yet tried it. I couldn't tell whether this instability was due to Java 7 or Eclipse. Since we typically run regression testing for releases on Max OS X, it's important to have a stable Java 7 available there. Another consideration is when will Apple move up to Java 7 by default, since that will make it relatively easy for Mac OS X users to upgrade. Fortunately, it is easy to run Eclipse under Java 6 and define run configurations against Java 7, which is what we'll need to do if Apple drag their feet much more.