docs: private static boolean hasZipExtension(String name) {
          int nameLen = name.length();
  
          // Need '.' plus at least three characters.
  
          if ( nameLen < 4 ) {
              return false;
          }
  
          // Need '.' plus at least six characters for ".spring".
  
          if ( nameLen >= 7 ) {
              if ( (name.charAt(nameLen - 7) == '.') &&
                   name.regionMatches(IGNORE_CASE, nameLen - 6, ZIP_EXTENSION_SPRING, 0, 6) ) {
                  return true;
              }
          }
  
          if ( name.charAt(nameLen - 4) != '.' ) {
              return false;
          } else {
              for ( String ext : ZIP_EXTENSIONS ) {
                  if ( name.regionMatches(IGNORE_CASE, nameLen - 3, ext, 0, 3) ) { // ignore case
                      return true;
                  }
              }
              return false;
          }
  
          // return name.matches("(?i:(.*)\\.(ZIP|[SEJRW]AR|E[BS]A|SPRING))");
      }