This YouTube video explains how to write a Python3 question: https://www.youtube.com/watch?v=Wpp5L3gNfoQ&t=273s&pp=0gcJCU0KAYcqIYzv. To instead write a "Hello world" Java question, type you need to change only two things:
- Select "Java program" as the question type instead of "Python3"
- Define only a single test case, with no Test code or Input, and with the Expected Output being "Hello world".