Sonar flag "Bad practice": Usage of GetResource in XYZ may be unsafe if class is extended

Question

Sonar is indicating this error in our Java project. Any suggestion for safe programming is welcome!

URL url = getClass().getResource("/myWonderfulResource.txt");
if (url == null) {
  throw new IllegalStateException("File not found: /myWonderfulResource.txt");
}

Answer 1

Make the class final so it can not be extended. The warning is there to prevent the extended class (potentially) trying to use inexistent resources.