> Yah that is why oracle uses it's own jdk (vm) when is installed

I suspect that reason is more the garbage collector and JIT compiler
than class file version.

> Maybe in the future , firebird could use one of the open source vm's
> http://www.gnu.org/software/classpath/
> http://www.kaffe.org/

We should pick the one that provides the best performance. And
provided alternatives to Sun's HotSpot, the one that has better
alternative to JNI and acceptable license.

Roman