This is cool! I've often felt tempted to build something like that. I'm disappointed by how overpriced and terrible commercial thermostats are - try finding one that can actually switch from cool to heat automatically, isn't super-cumbersome to set up, and doesn't cost several hundred bucks.

It's also a bit sad how hard it seems to be to get Google Home to be able to control custom gadgets.

And combining Python scripts with a Spring Boot webapp - why? Seems like a good application for Flask. Why use 2 languages when 1 can do the job?