code: public static boolean isUnsignedInt (@Nullable final String sStr)
    {
      if (sStr != null)
        try
        {
          Integer.parseUnsignedInt (sStr, DEFAULT_RADIX);
          return true;
        }
        catch (final NumberFormatException ex)
        {
          // fall through
        }
      return false;
    }
docs: Checks if the given string is a numeric string that can be converted to an
  unsigned long value with radix {@value #DEFAULT_RADIX}.
  
  @param sStr
  The string to check. May be <code>null</code>.
  @return <code>true</code> if the value can be converted to a valid value