I think its a springboot REST application. But i dont see the annotations, so i wonder whether it really is one. Anyway, assuming that you would be adding the annotations once u get past compiler errors.

So, for this compile error, I would recommend get and IDE like STS - https://www.geeksforgeeks.org/how-to-download-and-install-spring-tool-suite-spring-tools-4-for-eclipse-ide/ this might help. and ensure u have java set in the eclipse like:enter image description here .

Then try Project > BuildAll .. from there u can start debugging if your compiler does not give any more errors in STS