code: public String getNexusUrl() {
          if (line == null || !line.hasOption(ARGUMENT.NEXUS_URL)) {
              return null;
          } else {
              return line.getOptionValue(ARGUMENT.NEXUS_URL);
          }
      }
docs: Returns the url to the nexus server if one was specified.
  
  @return the url to the nexus server; if none was specified this will
  return null;