404 description The requested resource is not available

Приветствую. Подскажите такой вопрос. Использую Glassfish. Ниже код сервлета и web.xml. Подскажите почему при переходе по url http://localhost:8080/?one=3 выдает 404 description The requested resource is not available?

package servlet; 
import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import java.io.IOException; 
import java.io.PrintWriter; 
public class CalcServlet extends HttpServlet { 
@Override 
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
processRequest(req, resp); 
} 
protected void processRequest(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{ 
resp.setContentType("text/html; charset=UTF-8"); 
String one = req.getParameter("one"); 
System.out.println(one); 
PrintWriter out = resp.getWriter(); 
try { 
out.println(one); 
} finally { 
out.close(); 
} 
} 
}

web.xml:

<?xml version="1.0" encoding="UTF-8"?> 
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" 
version="3.1"> 
<servlet> 
<servlet-name>CalcServlet</servlet-name> 
<servlet-class>servlet.CalcServlet</servlet-class> 
</servlet> 
<servlet-mapping> 
<servlet-name>CalcServlet</servlet-name> 
<url-pattern>/</url-pattern> 
</servlet-mapping> 
</web-app>