As my work of going down the list of JEE specs is hitting dwindling returns, I decided to give a shot to implementing the Jakarta Transactions spec. This one's a little spicy for a couple of reasons, one of which is that it's really a codified implementation of another spec, the X/Open XA standard, which is an old standard for transaction processing. As is often the case, "old" here also means "fiddly", but fortunately it's not too bad for this need. Another reason is that, unlike with a lot of the specs I've implemented, all of the existing implementations seem a bit too heavyweight for me to adapt. I may look around again later: I could have missed one, and eventually GlassFish's implementation may spin off. In the mean time, I wrote a from-scratch implementation for the XPages JEE project: it doesn't cover everything in the spec, and in particular doesn't support suspend/resume for transactions, but it'll work for normal cases in an NSF.

For a little while, I've had a task open for me to investigate the Jakarta Concurrency and MP Context Propagation specs, and this weekend I decided to dive into that. While I've shelved the MicroProfile part for now, I was successful in implementing Concurrency, at least for the most part.