With the recent announcements from Oracle side, we have started to work on a plan for phasing out migration from the Sun JVM to the whatever reliable and free alternative we will end up with.
Open JDK will obviously become a major option, now that IBM has announced its focus on it, but it will take some time for that to be an alternative to Sun's existing JVMs, in terms of stability and reliability.
Are there any JVM options out there, which are powering real life mission critical applications? IBM's JVM can't be used on other than IBM hardware as far as I know.
If you know of any alternatives which may help us depict a picture of the JVM domain, your feedback would be much appreciated.
We have large work on Eclipse ecosystems, backed up with jboss application servers and we're really interested in knowing our options now that access to Oracle's JVM is likely to require licencing fees.
If it is any help, I run OpenJDK in production now, it's been pretty stable. (I was originally running Sun JVM, but there is a long-overdue bug that was crashing my app, so I had to switch.)