When the class is declared in the deal for example com.acme.instance, Then you definately will have to use the entire classname together with all lessons and interfaces in the superclass hierarchy (e.g. see Java course is present in classpath but startup fails with Mistake: Couldn't locate or load principal course) https://artwork92467.blazingblog.com/33820280/the-fact-about-power-supply-uninterruptible-that-no-one-is-suggesting