code: public static boolean isValid(Class<? extends AbstractPlugin> pluginClass) {
          return pluginClass != null && pluginClass.isAnnotationPresent(Plugin.Name.class) &&
                  checkModifiers(pluginClass) && checkFieldsWithDataAnnotation(pluginClass);
      }
docs: Verify plugin class. Plugin with resources plugin should not be private, abstract or interface.
  Also class should be annotated with {@link Plugin.Name}
  annotation. Returns true if given class is valid plugin, false otherwise.
  Plugin class should not be null.