code: private String getPackageName(ObjectMappableAnnotatedClass clazz) {
      PackageElement pkg = elements.getPackageOf(clazz.getElement());
      return pkg.isUnnamed() ? "" : pkg.getQualifiedName().toString();
    }
docs: Get the package name of a certain clazz
  
  @param clazz The class you want the packagename for
  @return The package name