docs: private Set<String> buildClassSet(BugCollection bugCollection) {
          Set<String> classSet = new HashSet<>();
  
          for (Iterator<BugInstance> i = bugCollection.iterator(); i.hasNext();) {
              BugInstance warning = i.next();
              for (Iterator<BugAnnotation> j = warning.annotationIterator(); j.hasNext();) {
                  BugAnnotation annotation = j.next();
                  if (!(annotation instanceof ClassAnnotation)) {
                      continue;
                  }
                  classSet.add(((ClassAnnotation) annotation).getClassName());
              }
          }
  
          return classSet;
      }