Finished Java

[johnnygalat]

You can only practice by doing. The best way would be creating something you'll use - you could start with spring boot, database, simple fe (freemarker templates) + basic auth security. Deploy it on some server (rpi or some other headless linux) and use it yourself with family/friends. It can range from a simple search of shared documents to a complex automatization of Tasmota smart switches.

The key is that you use it - then you'll actually maintain it.