...
Open Activator.java and update the code with your package declaration as well as occurrences of your plug in class name. The sample code implements an annotation operation, so Activator.java registers service for Alignment, Annotation and ProbeSet means this plugin is designed only for these 3 types of annotations. Actually this SamplePlugin derives from the existing IGB plugin named OverlapAnnotationOperator which you can find it in the plugins folder.
There are also many other different types of operation for annotation and graph created as a plugin or not, such as MergeAnnotationOperator plugin and XorOperator in core folder then com.affymetrix.genometryImpl.operator package.
Your plugin class name is inserted in the file as shown in the following code, as "MyPlugin".
...