Text staring with % is not decoded in java UTF8. But if % is entered following characters UTF8 decodes it correctly. I entered "%kj" in the form field
param.message=encodeURIComponent(message);
String message = URLDecoder.decode(request.getParameter("message"), "UTF-8");
Getting this error:
java.lang.IllegalArgumentException: URLDecoder: Illegal hex characters in escape (%) pattern - For input string: "kj"