BWINF is a German CompSci challenge targeted at schools.
I just did it for fun.
Task sheets are here https://bwinf.de/fileadmin/BwInf/38/BwInf38-Aufgabenblatt.pdf
Additional material here https://bwinf.de/bundeswettbewerb/38/1-runde/material-381/
Well, its maven, go figure. I used jdk 13 with preview features tho, so you wanna watch out for that.