Clojure+Java Emacs setup

I have always kept Clojure and Java development projects separate and advise that this is the simplest approach. Then simply add the java library as a dependency to the Clojure project.

Emacs and Java with LSP seems to be very comprehensive (more so than Clojure & LSP, although that does keep improving)
https://github.com/emacs-lsp/lsp-java

There is a very interesting demo video showing Emacs and Java development

Again, I’d avoid polyglot projects as they are often a source of many small issues during development, testing, CI and deployment tasks.