code: public static String toUpperCase(final String value) {
          final char[] chars = value.toCharArray();
  
          for (int i = 0; i < chars.length; i++) {
              chars[i] = UPPER_CASE_CHARS[chars[i]];
          }
  
          return new String(chars);
      }
docs: In html, the tag characters are supposed to use a limited number of
  characters like 'a'-'z', 'A'-'Z', '0'-'9', '.', ',', '-' etc...<br>
  This method gains performance than the native
  {@code String.toUpperCase()} method.
  
  @param value
  The String to lower case
  @return The upper case string
  @author WFF