After an enormously unpleasant debugging cycle, we realized that the JIT compiler was incorrectly eliminating a call to System::arrayCopy, which meant that some fields were left uninitialized. But only when JIT compiled, non-optimized code ran fine.
This left us with three possible upgrade paths:
* Upgrade thrift to a newer version and hope that JIT compilation works well on it. But this is a nightmare since A) thrift is no longer supported, and B) new versions of thrift are not backwards compatible so you have to bump a lot of dependent libraries and update code for a bunch of API changes (in a LARGE number of services in our monorepo...). With no guarantee that the new version would fix the problem.
* File a bug report and wait for a minor version fix to address the issue.
* Skip this LTS release and hope the JIT bug is fixed in the next one.
* Disable JIT compilation for the offending functions and hope the performance hit is negligible.
I ultimately left the company before the fix was made, but I think we were leaning towards the last option (hopefully filing a bug report, too...).
There's no way this is the normal reason companies don't bump JRE versions as soon as they come out, but it's happened at least once. :-)
In general there's probably some decent (if misguided) bias towards "things are working fine on the current version, why risk some unexpected issues if we upgrade?"
