It's time for me to come clean.
ALL of my lessons were created in 2020 (I think) using this website:
I am pretty sure that educators are covered under Fair Use:
I worked really hard to understand everything (over time some things have definitely decided to leave my brain) and add a little "flair" to make my website more interesting.
So, if you're wondering where I learned all this Java stuff, the answer is simple.
Runestone Academy (aka CSAwesome).