We are thinking of transitioning a large product from relying on Sun's JVM to JRockit. I'm not naive enough to believe that this is going to be a smooth transition (though I'd love to be wrong).
What issues should we watch out for or focus our regression testing on?
Well, of course you have unit tests right? :-)
I have used JRockit somewhat just for "fun" and have never had issues. From what I can see it is used in a number of apps of a wide variety so it should probably just work. It seems that it has also passed the JCK (the compatibility tests from Sun), so it should be smooth.
Areas that I would think of for breaking would be:
The file system, threading, etc... are all the parts of the VM that integrate with the underlying OS. If they use the Sun code then less chance of issues.
I would bet that the transition does go smoothly.
As I always say: There is only one way to find out: do it!
The transition should take about what... 30 minutes ( you just install JRockit and change the path somewhere right? )
You should be ok.
I had problems in the past with JDBC which were extremely strange ( because the problematic code was in the PreparedStatement reference that as we all know is just an interface. The underlaying driver was exactly the same.) I've got this strange error messages all over the place about the insert intostatement.
To be honest there was another variable here, I was migrating from Java 1.2.2 to Java(JRockit) 1.4 and yet, I think I shouldn't have had all those problems.
But again, it should be fast enough to find out. In my case I saw I had these problems in < 5 minutes and since that was just an experiment ( I attended to this BEA developers day when they talked about the great features JRockit had ) I just dismissed it.