code: private long computeConfigurationLastModified(List<Resource> configurations) {
          long result = 0;
          for (Resource configuration : configurations) {
          	try {
                  long currentConfigurationLastModified = configuration.lastModified();
                  if (currentConfigurationLastModified > result) {
                      result = currentConfigurationLastModified;
                  }
              } catch (IOException ioex) {
                  logger.warn("Error while reading last configuration modification date.", ioex);
              }
          }
          return result;
      }
docs: Computes the last modified date of all configuration files.
  
  @param configurations the list of available configurations as Spring resources
  @return