jfli-abcl, basically, allows one to quickly create Lisp function wrappers for Java classes.
E.g.
(def-java-class "java.sql.DriverManager") (use-package :|java.sql|) (DriverManager.getConnection ...)
The benefit over java:jcall and JSS is that it looks more-or-less like normal Lisp function calls, pretty similar to a wrapper you could write yourself. Also, potentially, it might carry less runtime overhead because everything can be resolved at compile-time.
And if you use SLIME, auto-completion works. It doesn't like mixed case, though, so you need to write it like (|java.sql|:drivermanager.getcollection ...) Still, better than nothing.
As far as I can tell, jfli-abcl isn't currently maintained. But as I'm used to jfli-abcl I maintain my own version with some fixes.
If there is any interest in jfli-abcl I could, perhaps,. publish my version and polish it a bit.
(I'm personally not interested in new-class functionality which allows one to create Java class from Lisp.)
(I've found this updated version: https://gist.github.com/avodonosov/abcl-idea/blob/master/src/abclidea/lisp/j... But haven't yet checked if it works with latest ABCL and what are improvements against old one.)