code: public static ErrorCodeAttribute createErrorCodeAttribute(byte errorClass,
  			byte errorNumber, String reasonPhrase) throws StunException {
  		ErrorCodeAttribute attribute = new ErrorCodeAttribute();
  
  		attribute.setErrorClass(errorClass);
  		attribute.setErrorNumber(errorNumber);
  
  		attribute.setReasonPhrase(reasonPhrase == null ? ErrorCodeAttribute
  				.getDefaultReasonPhrase(attribute.getErrorCode())
  				: reasonPhrase);
  
  		return attribute;
  	}
docs: Creates an ErrorCodeAttribute with the specified error class, number and
  reason phrase.
  
  @param errorClass
  a valid error class.
  @param errorNumber
  a valid error number.
  @param reasonPhrase
  a human readable reason phrase. A null reason phrase would be
  replaced (if possible) by a default one as defined byte the
  rfc3489.
  @return the newly created attribute.
  @throws StunException
  if the error class or number have invalid values according to
  rfc3489.