This week's book giveaway is in the Java in General forum. We're giving away four copies of Helidon Revealed: A Practical Guide to Oracle’s Microservices Framework and have Michael Redlich on-line! See this thread for details.
What are you trying to debug? You can't (and don't want to) turn on debug for everything. Lots of information is logged to the server log. By default, I think only Error and Notice messages are also printed to the terminal (stdout), but you can change this from the console.