If you want to remove an existing cookie, you can use the method setMaxAge() of that cookie object to set its timeout to zero.Example

<%@page import="javax.servlet.http.Cookie"%>

 <%
     Cookie[] cookielist = request.getCookies();
     if (cookielist!= null) {
         for (int i = 0; i < cookielist.length; i++) {
             cookielist[i].setMaxAge(0);
             out.println(" cookie is removed");
           }
        }
%>