folder. That file contains a single line with the full canonical name to the RequiresMethodAnnotationProcessor : com.osbcp.requiresmethodannotation.RequiresMethodAnnotationProcessor To give a better explanation, when exporting the JAR -file, the specific file will look like this: The full source code can be viewed here: https://github.com/corgrath/Requires-Static-Method-Annotation/blob/master/META-INF/services/javax.annotation.processing.Processor/ The proper way to debug is done by