According to Wikipedia, proof of concept (POC or PoC), also known as proof of principle, is described as:

A realization of a certain idea, method or principle in order to demonstrate its feasibility, or viability, or a demonstration in principle with the aim of verifying that some concept or theory has practical potential. A proof of concept is usually small and may or may not be complete.

As a Java developer, I utilize this repository to test various designs and implementations relevant to the Java ecosystem.