code: private void validateParameterProviders() {
      Set<String> parameterNames = new HashSet<>();
      for (ParameterProvider provider : this.parameterProviders) {
        Set<String> applicationIdsOfThisProvider = new HashSet<>();
        for (Parameter<?> parameter : provider.getParameters()) {
          if (StringUtils.isNotEmpty(parameter.getApplicationId())) {
            applicationIdsOfThisProvider.add(parameter.getApplicationId());
          }
          if (parameterNames.contains(parameter.getName())) {
            log.warn("Parameter name is not unique: {} (application: {})", parameter.getName(), parameter.getApplicationId());
          }
          else {
            parameterNames.add(parameter.getName());
          }
        }
        if (applicationIdsOfThisProvider.size() > 1) { //NOPMD
          log.warn("Parameter provider {} defines parameters with multiple application Ids: {}", provider,
              applicationIdsOfThisProvider.toArray(new String[applicationIdsOfThisProvider.size()]));
        }
      }
    }
docs: Validate that application ids and configuration names are unique over all providers.