Java Wrapper Class: getParameterValues(String name) not working

Question

I have created a wrapper class to validate all the input parameters by assigning them into an array. I am getting request from Filter class. getParameterValues is not working which I am using to get the request parameters into an array.

        public class XSSRequestWrapper extends HttpServletRequestWrapper {  

            public XSSRequestWrapper(HttpServletRequest servletRequest) {
              super(servletRequest);       
            }

Following code works fine

             public String getParameter(String name) {
                // TODO Auto-generated method stub
                                    return super.getParameter(name);
             }  

Following doesn't work at all

            public String[] getParameterValues(String name) {
             // TODO Auto-generated method stub

                  return super.getParameterValues(name);
            }

Following is the filter.java

 //@WebFilter("/filter")
public class filter implements Filter {


    public filter() {
        // TODO Auto-generated constructor stub
    }


    public void destroy() {
        // TODO Auto-generated method stub
    }


    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
                    chain.doFilter(new XSSRequestWrapper((HttpServletRequest) request), response);


    }
    public void init(FilterConfig fConfig) throws ServletException {
        // TODO Auto-generated method stub
    }

}