Functional interfaces are allow Java programmers to write methods whose arguments are lambda functions. How does this work, and why would it be useful?

This was inspired by a short chat I had with a coworker, trying to give a simple, 15 minute explanation of something that took me a decade to wrap my head around due to poor teaching resources online. Async programming in modern “industrial” languages is shrouded in magic, abstractions, and years of atrocious...

This is a photograph I originally posted on Instagram