I use emacs for Java and Scala development with LSP quite successfully, and VS Code's support for language servers is as good as they come. Is it primarily debugging that's the impediment to switching for you?
While we're on the subject - not that many people are aware of it yet, but VS Code has a debugger protocol similar to LSP for pluggable IDE-agnostic debuggers.
Me too, the Spacemacs layers are really nice actually. Java and Scala ain't gonna keep me away from dired, macros, magit, org, nor my favorite shortcuts :D
Speaking of, I had a Spark lab for school and it was too powerful for my machine, so I ssh'ed into the school's computer and ran a spark-shell from there, in an emacs split. Then with a macro, it was easy to "send region" or "send buffer" to the ssh'ed spark-shell. I made a quick script for that actually, it was so convenient: https://github.com/tbinetruy/config/blob/master/spacemacs/sp...
And that's why I love my emacs, I can just do stuff like that so easily :D
I have some time off soon and there's a project I have planned that will use Scala. What LSP server do you recommend, and are you using it with lsp-mode or with eglot?
I'm using lsp-mode and the Eclipse JDT language server. lsp-java is great and the maintainer is very responsive to PRs and feedback.
For Scala I use Ensime at work and have been playing with metals at home. The latter is still very much under active development and you'll likely have to put up with Ensime's quirks for a complicated Scala codebase.
https://microsoft.github.io/debug-adapter-protocol/
https://github.com/Microsoft/debug-adapter-protocol/blob/gh-...
I hope this takes off. Between it and LSP, pretty much any text editor can be an IDE with little effort.