[jillesvangurp]

Like with any language pick something you want to build and then build it and perhaps don't get too carried away with the level of ambition. Intellij Community edition is fine. It's what I use. Some of the spring support in the commercial edition is nice but I don't really miss it.

If you have some old Java code, a good way to get started is converting some of that to Kotlin in intellij. You'll get familiar with the syntax that way and you can figure out the language as you go. Mostly things are a bit different but not that much. Nicer too. I remember my first afternoon of converting a few tests and then really liking what I saw. That's five years ago.

If you are doing a greenfield project, I'd suggest starting with a simpler framework like ktor. Especially if you come from a node.js or go background. Ktor is very nice. No annotation magic, easy to understand, and you can write a simple http service in a few lines of code. There's nothing wrong with Spring Boot (I use it), but it's just a lot to wrap your head around and figure out. Even just deciding on which bits you should and shouldn't work involves a lot of decision making. It has a lot of legacy features at this point.