This is stupid but i think is my best idea yet.

So i have an old orange pi, with only 256m memory. Its running a few tasks i need but i wanted to use it for controlling a few things from my phone (lights and powering on my pc) so i thought i would make a server for that. Now mind you, my shirt doesnt say "lightweight backend language", so there was no way the pi couldve handled a struts server. I was digging around and found that php has a shell_exec command. Then it clicked, and i wrote the whole system like
shell_exec("java -jar someprocess.jar"). Now this sounds really stupid but it works and php is really light so it doesnt even slow it down that much.

Thinking about making this into some kinda server/framework/something just for fun.