Out of curiosity, why is Postgresql's Java support so poor?
To trampoline off what others have said: it gets implemented and maintained if people want/need it.
But I feel like I have a little more insight into _why_ people aren't taking the effort, based on experience at my last job.
We were interested in both pl/Java and pl/PHP. In theory, both of those would allow us to leverage both existing codebases and existing developer skills. We were looking at taking an active role in maintainership of these two languages to facilitate our use.
In practice, the amount of code in existing code bases that would be reused for stored procedures turned out to be very low. Additionally, the number of developers who had difficulty adapting to plPGSQL programming was 0. As a result, we found that, in practice, the existing pl/SQL and plPGSQL were _good_enough_ and there was so little benefit from using other languages that we couldn't justify the effort of ensuring they worked consistently.
From a meta standpoint, it feels like pl/Java and others are really neat ideas that simply aren't _necessary_ (although they're nice to have). When it comes down to work done for employer, it was just less effort to succeed by going the route of using the existing plSQL/plPGSQL, and employers are all about less money spent to accomplish the goal.
Other people may have other opinions or stories or whatever. That's mine.
I'm very glad you posted this because I was thinking the same but needed someone to reinforce my views. pl/pgsql is beginning to look like the lesser evil to getting pl/java to work. Sad but true.
I strongly believe that pl/java would catapult the expressiveness of triggers to a new level, but getting this off the ground will require the concerted effort of 2-3 dedicated developers.
I am strong sceptic. There is relative slow progress in JDBC driver, that is 100x more important project than PL/Java - so It is hard to believe, so there can be 3 developers, who start work on PL/Java.
and I am not sure if Java as stored procedures is living technology, It was designed as "esperanto", but it is supported only by Oracle after 14 years.
