code: public static String getMimeName(String encoding)
    {
      if (encoding == null)
        return null;
  
      String value = _mimeName.get(encoding);
      if (value != null)
        return value;
  
      String upper = normalize(encoding);
  
      String lookup = _mimeName.get(upper);
  
      value = lookup == null ? upper : lookup;
  
      _mimeName.put(encoding, value);
  
      return value;
    }
docs: Returns the canonical mime name for the given character encoding.
  
  @param encoding character encoding name, possibly an alias
  
  @return canonical mime name for the encoding.