code: public String parse() {
      Map<String, ClassConstraints> classNameToValidationRulesMap = new HashMap<>();
  
      for (Class clazz : classpathScanner.findClassesToParse()) {
        if (clazz != null) {
          ClassConstraints classValidationRules = new AnnotatedClass(clazz, options.getExcludedFields(),
            allRelevantAnnotationClasses).extractValidationRules();
          if (classValidationRules.size() > 0) {
            String name = options.getOutputFullTypeName() ? clazz.getName() : clazz.getSimpleName();
            classNameToValidationRulesMap.put(name, classValidationRules);
          }
        }
      }
  
      return toJson(classNameToValidationRulesMap);
    }
docs: Based on the configuration passed to the constructor model classes are parsed for constraints.
  
  @return JSON string for <a href="https://github.com/netceteragroup/valdr">valdr</a>