Can you explain "it doesn’t seem to work" and also provide a bit more detail on what you have actually tried? Is having a standalone clojure -T:build compile-java command sufficient for your needs, for example? (i.e., that you run manually as needed to work with your :dev REPL)

Sean, hi! I had no doubt that you would be the one to respond. 😃 Sorry, I was in a hurry yesterday and didn’t go into details, hoping that someone will just send me a link to the existing repo. In essence, the commands I tried completed without any errors (i.e. the classpath was assembled correctly), but as a result, the target directory did not appear anywhere in the project. And, yeah, so far I find having a standalone command / bb task sufficient for the project needs — I’ll overengineer this later on. 😂 So, I played around with this a little more today and came up with a working setup. Here it is!

├── components
│   └── happy-face
│       └── src
│           └── 
│       └── java-src
│           └── 
│       └── deps.edn
├── build.clj
└── deps.edn

@U04V70XH6, the only problem that remains is tests failing in IntelliJ IDEA with its own classpath, even though the compiled class file is available. NB: I still use a rather old IntelliJ version, 2020.2.4, that comes with Cursive of the time, which doesn’t understand Polylith projects quite well yet.

I scanned the IntelliJ’s classpath and it turned out to be a bit outdated (the brick’s src-java made it to there, but not the target/classes). I then double-checked that I have all aliases enabled in “Clojure Deps” tab and refreshed the project. Now my tests are back to life! 😃

@U04V70XH6, what best practices can you recommend for similar mixed Clojure/Java codebase projects in production development? Do you use Java in the World Singles codebase?

We do not use Java code at all at work, just lots of Java libraries. We've never felt a need to "drop down" to Java -- Clojure does all we need.