The POC ... Proof of Concept.
You're boss/architect/design authority comes to you on Tuesday after that three day weekend and says "I was reading up on Spring Boot this weekend. Looks neat. Should solve some problems for us. Lets do a POC."
You roll your eyes ... internally for fear of losing your job.
The reality is that Spring Boot and most other Open Source Software you can name is proven to work! The concept is that you want to use Spring Boot and you need to provide proof that it works is just silly. Really, what your boss is saying is that they want you to learn about that software and get to work implementing it.
Now, does the POC exist? Yes, of course it does. Let's say that same boss comes up to you and proposes combining two or three pieces of software that no one has EVER done before or has some new pattern of software to create, then yes, that's a proof of concept.
So next time, gently correct this misuse of POC to training.