code: public static String concat(String mainUrl, String... relativeUrls) {
          String concatenatedUrl = mainUrl;
  
          if (ArrayUtils.isNotEmpty(relativeUrls)) {
              for (String relativeUrl : relativeUrls) {
                  concatenatedUrl = concat(concatenatedUrl, relativeUrl);
              }
          }
  
          return concatenatedUrl;
      }
docs: Concats two or more urls, adding any "/" needed between them.
  
  @param mainUrl       the main url
  @param relativeUrls  the array of relative urls
  
  @return mainPath + relativeUrls...