java.lang.NumberFormatException: null with error status 500

I faced issue with submitting data from html to servlet Can’t This is my html file <input type="radio" id="add" …

Do session objects take resources in my application? Won’t garbage collector remove them?

I came across part in Head First JSP and Servlets page:241 where it says that we have to get rid of sessions as shown in this picture: Later on they present methods invalidate() and …

Redirect to certain page upon clicking “OK”

My Servlet – “ImportFile”: doPost(){ … … PrintWriter out = response.getWriter(); response.setContentType(“text/html”); …

Tomcat. ClassNotFoundException on importing class

I am writing my training project on Tomcat based java servlets and jsp’s using Visual Studio Code. Now I am working on logging. My project structure looks like this: webapps |—-ROOT |—-public …

Java servlets on Tomcat take to 404 error but it works fine on localhost

I have design a webApp with NetBeans IDE. It works fine on localhost, but when I deploy it on my host, trying to access the servlets give me a 404 error. My servlet dos include the URLpattern and the …

how to modify web.xml for multiple servlet

I just get confused about how to modify web.xml for multiple servlet. I got three servlet to handle three different jsp, but now only one servlet is effective.

Why does Spring MVC respond with a 404 and report “No mapping found for HTTP request with URI […] in DispatcherServlet”?

I’m writing a Spring MVC application deployed on Tomcat. See the following minimal, complete, and verifiable example public class Application extends …

Servlet get GET and POST’s parameters at the doPost method

My problem is when I’m trying to access a POST Variable with request.getParameter(“name”), it works perfectly. But in some conditions, when a POST request arrives at my application, I also need to get …

Tomcat 7.0.43 “INFO: Error parsing HTTP request header”

I use Tomcat 7.0.43 with a websocket application. My app works fine in Tomcat 7.0.42 but with 43 I get the following output when I try to access my server on websockets: Sep 16, 2013 3:08:34 AM org….

How to access a request attribute set by a servlet in JSP?

I’m trying to retrieve attribute values set by a servlet in a JSP page, but I’ve only luck with parameters by ${param}. I’m not sure about what can I do different. Maybe its simple, but I couldn’t …