Java Web Application Tutorial for Beginners

Filed Under: Java EE
Java Web Application

Java Web Application is used to create dynamic websites. Java provides support for web application through Servlets and JSPs. We can create a website with static HTML pages but when we want information to be dynamic, we need web application.

Java Web Application

The aim of this article is to provide basic details of different components in Web Application and how can we use Servlet and JSP to create our first java web application.

  1. Web Server and Client
  2. HTML and HTTP
  3. Understanding URL
  4. Why we need Servlet and JSPs?
  5. First Web Application with Servlet and JSP
  6. Web Container
  7. Web Application Directory Structure
  8. Deployment Descriptor

Web Server and Client

Web Server is a software that can process the client request and send the response back to the client. For example, Apache is one of the most widely used web servers. Web Server runs on some physical machine and listens to client request on a specific port.

A web client is a software that helps in communicating with the server. Some of the most widely used web clients are Firefox, Google Chrome, Safari, etc. When we request something from the server (through URL), the web client takes care of creating a request and sending it to the server and then parsing the server response and present it to the user.

HTML and HTTP

Web Server and Web Client are two separate softwares, so there should be some common language for communication. HTML is the common language between server and client and stands for HyperText Markup Language.

Web server and client needs a common communication protocol, HTTP (HyperText Transfer Protocol) is the communication protocol between server and client. HTTP runs on top of TCP/IP communication protocol.

Some of the important parts of the HTTP Request are:

  • HTTP Method – action to be performed, usually GET, POST, PUT etc.
  • URL – Page to access
  • Form Parameters – similar to arguments in a java method, for example user,password details from login page.

Sample HTTP Request:


GET /FirstServletProject/jsps/hello.jsp HTTP/1.1
Host: localhost:8080
Cache-Control: no-cache

Some of the important parts of HTTP Response are:

  • Status Code – an integer to indicate whether the request was success or not. Some of the well known status codes are 200 for success, 404 for Not Found and 403 for Access Forbidden.
  • Content Type – text, html, image, pdf etc. Also known as MIME type
  • Content – actual data that is rendered by client and shown to user.

Sample HTTP Response:


200 OK
Date: Wed, 07 Aug 2013 19:55:50 GMT
Server: Apache-Coyote/1.1
Content-Length: 309
Content-Type: text/html;charset=US-ASCII

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Hello</title>
</head>
<body>
<h2>Hi There!</h2>
<br>
<h3>Date=Wed Aug 07 12:57:55 PDT 2013
</h3>
</body>
</html>

MIME Type or Content Type: If you see above sample HTTP response header, it contains tag “Content-Type”. It’s also called MIME type and server sends it to the client to let them know the kind of data it’s sending. It helps the client in rendering the data for the user. Some of the most used mime types are text/html, text/xml, application/xml etc.

Understanding URL

URL is the acronym of Universal Resource Locator and it’s used to locate the server and resource. Every resource on the web has its own unique address. Let’s see parts of the URL with an example.

http://localhost:8080/FirstServletProject/jsps/hello.jsp

http:// – This is the first part of URL and provides the communication protocol to be used in server-client communication.

localhost – The unique address of the server, most of the times it’s the hostname of the server that maps to unique IP address. Sometimes multiple hostnames point to same IP addresses and web server virtual host takes care of sending a request to the particular server instance.

8080 – This is the port on which server is listening, it’s optional and if we don’t provide it in URL then request goes to the default port of the protocol. Port numbers 0 to 1023 are reserved ports for well-known services, for example, 80 for HTTP, 443 for HTTPS, 21 for FTP, etc.

FirstServletProject/jsps/hello.jsp – Resource requested from server. It can be static html, pdf, JSP, servlets, PHP etc.

Why we need Servlet and JSPs?

Web servers are good for static contents HTML pages but they don’t know how to generate dynamic content or how to save data into databases, so we need another tool that we can use to generate dynamic content. There are several programming languages for dynamic content like PHP, Python, Ruby on Rails, Java Servlets and JSPs.

Java Servlet and JSPs are server-side technologies to extend the capability of web servers by providing support for dynamic response and data persistence.

Java Web Development

First Web Application with Servlet and JSP

We will use “Eclipse IDE for Java EE Developers” for creating our first servlet application. Since servlet is a server-side technology, we will need a web container that supports Servlet technology, so we will use the Apache Tomcat server. It’s very easy to set up and I am leaving that part to yourself.

For ease of development, we can add configure Tomcat with Eclipse, it helps in easy deployment and running applications.

Go to Eclipse Preference and select Server Runtime Environments and select the version of your tomcat server, mine is Tomcat 7.

Eclipse-with-Tomcat

Provide the apache tomcat directory location and JRE information to add the runtime environment.

Now go to the Servers view and create a new server like below image pointing to the above-added runtime environment.

Eclipse-New-Server-Tomcat

Note: If Servers tab is not visible, then you can select Window > Show View > Servers so that it will be visible in Eclipse window. Try stopping and starting the server to make sure it’s working fine. If you have already started the server from the terminal, then you will have to stop it from the terminal and then start it from Eclipse else it won’t work perfectly.

Now we are ready with our setup to create the first servlet and run it on tomcat server.

Select File > New > Dynamic Web Project and use below image to provide runtime as the server we added in last step and module version as 3.0 to create our servlet using Servlet 3.0 specs.

First-Servlet-dynamic-web-project

You can directly click the Finish button to create the project or you can click on Next buttons to check for other options.

Now select File > New > Servlet and use below image to create our first servlet. Again we can click finish or we can check other options through the next button.

first-servlet

When we click on the Finish button, it generates our Servlet skeleton code, so we don’t need to type in all the different methods and imports in servlet and saves us time.

Now we will add some HTML with dynamic data code in doGet() method that will be invoked for HTTP GET request. Our first servlet looks like below.


package com.journaldev.first;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class FirstServlet
 */
@WebServlet(description = "My First Servlet", urlPatterns = { "/FirstServlet" , "/FirstServlet.do"}, initParams = {@WebInitParam(name="id",value="1"),@WebInitParam(name="name",value="pankaj")})
public class FirstServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
	public static final String HTML_START="<html><body>";
	public static final String HTML_END="</body></html>";
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public FirstServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		PrintWriter out = response.getWriter();
		Date date = new Date();
		out.println(HTML_START + "<h2>Hi There!</h2><br/><h3>Date="+date +"</h3>"+HTML_END);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
	}

}

Before Servlet 3, we need to provide the url pattern information in web application deployment descriptor but servlet 3.0 uses java annotations that is easy to understand and chances of errors are less.

Now chose Run > Run on Server option from servlet editor window and use below images for the options.

servlet-eclipse-server

servlet-eclipse-server-webapps

After clicking finish, the browser will open in Eclipse and we get following HTML page.

first-servlet-run

You can refresh it to check that Date is dynamic and keeps on changing, you can open it outside of Eclipse also in any other browser.

So servlet is used to generate HTML and send it in response, if you will look into the doGet() implementation, we are actually creating an HTML document as writing it in response PrintWriter object and we are adding dynamic information where we need it.

It’s good for a start but if the response is huge with a lot of dynamic data, it’s error-prone and hard to read and maintain. This is the primary reason for the introduction of JSPs.

JSP is also server-side technology and it’s like HTML with additional features to add dynamic content where we need it.
JSPs are good for presentation because it’s easy to write because it’s like HTML. Here is our first JSP program that does the same thing as the above servlet.


<%@page import="java.util.Date"%>
<%@ page language="java" contentType="text/html; charset=US-ASCII"
    pageEncoding="US-ASCII"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Hello</title>
</head>
<body>
<h2>Hi There!</h2>
<br>
<h3>Date=<%= new Date() %>
</h3>
</body>
</html>

If we run above JSP, we get output like below image.

first-jsp-run

The final project hierarchy looks like below image in Eclipse.

project-hierarchy-servlet

Download FirstServlet Project

We will look into Servlets and JSPs in more detail in future posts but before concluding this post, we should have a good understanding of some of the aspects of Java web applications.

Web Container

Tomcat is a web container, when a request is made from Client to web server, it passes the request to web container and it’s web container job to find the correct resource to handle the request (servlet or JSP) and then use the response from the resource to generate the response and provide it to web server. Then the webserver sends the response back to the client.

When web container gets the request and if it’s for servlet then container creates two Objects HTTPServletRequest and HTTPServletResponse. Then it finds the correct servlet based on the URL and creates a thread for the request. Then it invokes the servlet service() method and based on the HTTP method service() method invokes doGet() or doPost() methods. Servlet methods generate the dynamic page and write it to the response. Once servlet thread is complete, the container converts the response to HTTP response and send it back to the client.

Some of the important work done by web container are:

  • Communication Support – Container provides easy way of communication between web server and the servlets and JSPs. Because of the container, we don’t need to build a server socket to listen for any request from the webserver, parse the request and generate a response. All these important and complex tasks are done by container and all we need to focus is on our business logic for our applications.
  • Lifecycle and Resource Management – Container takes care of managing the life cycle of servlet. The container takes care of loading the servlets into memory, initializing servlets, invoking servlet methods and destroying them. The container also provides utility like JNDI for resource pooling and management.
  • Multithreading Support – Container creates a new thread for every request to the servlet and when it’s processed the thread dies. So servlets are not initialized for each request and save time and memory.
  • JSP Support – JSPs doesn’t look like normal java classes and web container provides support for JSP. Every JSP in the application is compiled by container and converted to Servlet and then container manages them like other servlets.
  • Miscellaneous Task – Web container manages the resource pool, does memory optimizations, run garbage collector, provides security configurations, support for multiple applications, hot deployment and several other tasks behind the scene that makes our life easier.

Web Application Directory Structure

Java Web Applications are packaged as Web Archive (WAR) and it has a defined structure. You can export above dynamic web project as WAR file and unzip it to check the hierarchy. It will be something like below image.

WAR-directory-structure

Deployment Descriptor

web.xml file is the deployment descriptor of the web application and contains a mapping for servlets (prior to 3.0), welcome pages, security configurations, session timeout settings, etc.

Thats all for the java web application startup tutorial, we will explore Servlets and JSPs more in future posts.

Update: Next tutorial in this series is Java Servlets Tutorial

Comments

  1. Shraddha Singh says:

    I appreciate your knowledge provided by you ,it’s really helpful for java leaning people

  2. Malashri says:

    Really Helpful article

  3. Sruthi says:

    Awesome one. It is simple and very effective. Still I have a query, you mentioned on using jsp instead of servlet for long responses. So how would the container know which jsp to use. I got a little confused here. Please help me.

  4. Matrix Sniper says:

    this is a nice post.

  5. jonathan says:

    How to consume rest API in eclipse dynamic web project?

  6. Shyla says:

    Simply Superb. The explanation is simple and very informative. Keep up the good work

  7. dario says:

    Very good , thanks

  8. Divyesh Aegis says:

    This article complete describer of the simple web application for Java. It covers Java web technologies, HTML and HTTP with first web application using Servlet and JSP example.

  9. Jithesh says:

    I am getting the below Error

    The project was not built since its build path is incomplete. Cannot find the class file for java.io.ObjectInputStream. Fix the build path then try building this project FirstServletProject Unknown Java Problem

    Kindly guide me

    1. Gaurav K says:

      In ‘Package Explorer’ tab right click on your project name.
      Go to Build Path > Configure Build Path, open the ‘Libraries’ section of the Java Build Path.

      In Libraries section you can see the list of libraries added.

      Click on ‘Add Libraries…’ and select the ‘JRE System Library’ type to add, then click on ‘Next’ and choose ‘Workspace Default JRE’. and click on ‘Finish’.

      (If you can see that JRE System Library is already there then kindly remove it and follow the above steps.

      I did the same when I had faced this problem.

      I do not know why this happened but simply removing the current library and adding the default one worked.

      Referred: Eclipse Java EE IDE for Web Developers. Version: Oxygen.3a Release (4.7.3a).)

      Hope this helps!

  10. Cina says:

    Thank you

  11. Kartik Arora says:

    Thank you so much!
    This is a wonderful start.

  12. RIYAS K T says:

    HTML is the common language between server and client and stands for HyperText Markup Language.

    typo HTML >> it is http rt?

    1. kaushal says:

      http is the protocol or let say the method through which the common language HTML is shared between client and the server.

  13. Alex says:

    I had so many mistakes in java but nowadays it’s improving.

  14. tests4geeks says:

    Hi, great blog post. It’s a fantastic tutorial. You really had my head scratching so I’m going to beaver away later and dig right into it.

    I run a small website that creates AngularJs tutorials and it might compliment what you are doing here. You and your readers may find the tutorials useful. You can find them here:

    https://tests4geeks.com/angular-2-tutorial/
    https://tests4geeks.com/angular-google-maps-tutorial/
    https://tests4geeks.com/single-page-application-using-angularjs-tutorial/

    Thanks again for the great post. I look forward to reading more of your articles in the future.

  15. Quang Lai says:

    thank you, my Idol.
    I will still follow you to learn a lot of Java experience.
    Regards.

  16. Jijo says:

    The content is very simple to understand. Thanks a lot for this, it really helpfull.

  17. Strong says:

    Hi
    Thank you for your awesome post, I do enjoy a lot from it.
    However I do have a question: When I get that hello world example work, it only shows: Served at: /FirstServletProject in the page after clicking run. Is that the result we are supposed to get? If not, could you please help me of what is wrong with it? Thanks a lot.

  18. Srini says:

    Very crisp and nice

    1. cvkrishna says:

      you try this pgogram sucsess full run

  19. priya says:

    I executed the firstServlet program but getting 404 Not found error. Kindly suggest why error is coming.

    1. saurav says:

      I am also getting this same error! Perhaps we are doing some common mistake.
      With Error 404 : In description i am getting: The requested resource is not available.

    2. saurav says:

      I have solved mine..After solving this silly mistake ..
      You need to give complete path upto class name like : http://localhost:8080/FirstDynamicProject/FirstServlet
      FirstServlet is class name…

    3. Eduardo Serrano says:

      You are getting an error because the author of this post is very sloppy and didn’t took the time to put the correct URLs.

      http://localhost:8080/FirstServletProject/FirstServlet
      http://localhost:8080/FirstServletProject/jsps/hello.jsp

      1. Pankaj says:

        It’s present in all the images, also if you read the post and learned from it, you can easily figure it out yourself.

        @WebServlet(description = "My First Servlet", urlPatterns = { "/FirstServlet" , "/FirstServlet.do"} and “Understanding URL” section.

  20. hossein says:

    Hi
    thanks for this shorthand explanation.But i have a question.
    Are servlet and jsp relevant?
    I already learned java SE and i want to learn java EE .please guide me
    where should i start from?

  21. rusk says:

    Excellent,
    really very helpful, exactly what I needed.

  22. sandy says:

    simple explanation ,I got it easily sir thanks

  23. RRR says:

    Hi,
    This looks like a good tutorial, except for one thing. You are calling it a beginning tutorial but you are leaving out a very important detail that as beginners in dynamic web development, we would have no clue to set up. This is Eclipse and Tomcat. I have no idea how to get this or what to do. I could spend hours or days to figure it out but it seems like this would be a very important and helpful topic to include in this beginners tutorial. I wondered if there was a way to set up something to simulate a client/server system to practice web development. I’m assuming that Tomcat is some kind of server, but where and how do you get it and set it up for the way you are telling us to use it???

    Please respond !

    Thank you!

    RRR

    1. Pankaj says:

      If someone is looking to start with “Java Web Development”, I assume that he should have understanding of java and Eclipse IDE. Just search for “tomcat download” and you will get it within 2 mins.

  24. ziara says:

    sir
    Thankyou so much
    Its very useful to the beginners like me. simple presentation makes it easier to learn

  25. sumit says:

    thank u very much

  26. mahendra sharma says:

    Can i move a wordpress site http://songlers.com to a java site????? is there any solution which can help me to move or import this site to java web server or to a java cms.

  27. FUNSO STEPHEN IYAJU says:

    This is great Pankaj. I find it very helpful and interesting. Thanks man

  28. Sachindra says:

    Everything is Crystal Clear.. Simple, easy a,d understandable. I Completed learning Servlet and JSP, but few topics was still unclear and i was in fix . Now this post clear my all doubts . Thank you very much Mr Pankaj . Good job DUDE .:) Keep writing ..
    Regards Sachindra N. Pandey

  29. snega says:

    thank u for me to undersatnd the topic..

  30. israel says:

    excellent tutorial! thanks!

  31. Aboobacker Cheethayil says:

    Good Job. Explained in a simple way.

  32. Khaninkit says:

    Nice tutorial
    For me that didn’t know about JSP before.
    Thank you.

  33. Pavel says:

    Thanks,very helpful!

  34. Deepa Mohan says:

    It is very useful and 🙂
    Thanks:)

  35. Abir says:

    Helpful and clear and precise. Thanks 😀

  36. bill says:

    Very straight forward approach. Clear concise, well done and thanks.

  37. RAKESH JALCHHATRI says:

    Very Nice and very useful explanation.

  38. Pavel says:

    Thank you a lot for good explanation how to do WEB project using JSP on Eclipse. Good example how tutorials have to be made.
    Thank you!!!

  39. Rokon says:

    Thank You Dada for your clear and precise tutorial.
    #Respect and Gratitude from Bangladesh

  40. skini says:

    I am confused between web server and weB container, tom cat is a web container or server ? Please explain

    1. belhassen bouteraa says:

      tomcat is a container
      web server contains the container(tomcat)
      the web server intercept the http request , the container do his work and reply

    2. Ash says:

      tomcat is a server

  41. Imma says:

    I real enjoyed it, but i encounter an error “Server Tomcat v7.0 Server at localhost failed to start.” how can i fix it,, i tried several solutions from different communities like deleting .snap file and temp0 folder and even deleting the server and reconfiguring it, but still i didnt fix it.

  42. Arpita says:

    Is there any tutorial for Jsp Servlets with Gradle in Eclipse IDE

    1. Jean de Klerk says:

      Hi Arpita,

      If you’d like an example of JSP servlets being server with gradle as your build tool, check out https://github.com/jadekler/git-java-websiteskeleton. This is a pretty light skeleton that uses gradle as the build tool serving JSP through Spring’s WebMVC layer.

  43. balwinder singh says:

    Very nice and helpfull tutorial

  44. glory says:

    Thank u very much…

  45. Dada says:

    Very nice and helpfull tutorial

  46. Rahul Pathak says:

    Thank you very much………………….
    this article gives me correct thinking direction towards web application…………
    Looking for more explosure………..

  47. Vasiliy says:

    The good lesson! Please tell me how to run the app on a VPS/VDS?

  48. Akshata says:

    Hi Pankaj,

    For the Date application which you have created, I want to give one URL or Link using which any person can access this application. So how can I provide a link for this? PLease mail me. I need this urgently. Thank you.

  49. Poozone says:

    I was blind but now I see! Thank you for clear and transparent information, nicely served 🙂

  50. Ankita says:

    Hello Pankaj,

    I am very new to this technologies and I am keen to learn it more so please share your more blogs for web application.

    I would be really glad.

  51. Ali says:

    It is really great and easy to understand . I got so many things .I wish you my best , Dear friend.

  52. Arshi says:

    Very nice Article.Simple language and easy to grasp.

  53. Java Belazy says:

    Hi pankaj,

    How will we use application.resources to our web application?

  54. Java Belazy says:

    nice tutorial…
    It truely helped me

  55. Ravi Sindhe says:

    vey nice ..simple

  56. Shreya says:

    HTTP Status 404 – /FirstServletProject/

    ——————————————————————————–

    type Status report

    message /FirstServletProject/

    description The requested resource is not available.

    ——————————————————————————–

    Apache Tomcat/7.0.55

    This is the error I am getting. Could you please provide a possible solution?

    1. Pankaj says:

      Your web app servlet context is something else

      1. Akshay says:

        I am also getting the same error can you please tell the steps to resolve this issue.

        1. Haider says:

          If you are using windows/eclipse change the link to FirstServlet.java in annotation of the Servlet class.

          1. yashwanth nemani says:

            where should I make the change exactly?? Thanks.

    2. Brian says:

      The issue is that the author called the project FirstServletProject in the create new dynamic web project image, but coded it as FirstServlet

  57. Suren says:

    I’m new to Java / Web technologies. After searching several web sites i found this article is very simple and easy to follow. Thanks a lot.

  58. SATPAL says:

    GREAT TUTORIAL FOR STARTER………

  59. chaitra says:

    I am getting this error. Please help. WebInitParam cannot be resolved to a type

    1. Pankaj says:

      Make sure your servlet container is Servlet3 complaint, use tomcat-7 or above versions.

  60. Mayyank says:

    Nice Tutorials, but if you want to clear your concept click on the like

  61. misaochan says:

    I’m getting this error:

    HTTP Status 405 – HTTP method GET is not supported by this URL

    ——————————————————————————–

    type Status report

    message HTTP method GET is not supported by this URL

    description The specified HTTP method is not allowed for the requested resource.

    ——————————————————————————–

    Apache Tomcat/7.0.47

  62. right_now says:

    Nice tutorial but you shouldn’t have to worry about these types of things anymore… it’s time consuming. Use the Jigy Generator to create your project and everything will be completely configured for you. Jigy Generator reverse engineers your database to create all your DAO’s, domain objects and validators for you. Plus you have certain things that just work out of the box like login, authentication, file upload etc. You can download the project at http://www.getjigy.com

    1. Harshad says:

      I am facing challenge in generating eclipse project using Jigy Generator 1.0.4. After providing the mandatory information on the create project page, the download page never appears. The orbiting hour glass overlay never goes away. (Sidenote: I checked using firebug, the HTTP request received a response “Success”.)

  63. Don says:

    what if your version of Apache tomcat is not listed in Eclipe–>Window–>Preferences–>Server–>RTE–>Add–>Apache?

    Thanks,

    1. Pankaj says:

      Try to use the nearest version from the list, it should work.

  64. stalin says:

    Hi Sir,

    Can you please make all the tutorials and interview questions as downloadable “PDFf” files then it will be very useful. Thanks.

  65. Kishore says:

    Hi Pankaj,

    It is really good and useful article. Good that you have taken up the latest servlet3.0 examples. Really helpful.

  66. sabin elias morris says:

    pankaj i like your help to the people who want knowledge you are nice one god bless you.

    ok my problem is me i need to develop software of internet tv as my project so java is enough in my project or what other programming language which are better for my project like html and java script i need your help teacher

  67. Sri says:

    Nicely done Pankaj !

  68. Aravind says:

    Hi Pankaj,

    I have a special requirement in my project where I want to establish navigation between 2 different web apps.
    I have web app1 which will be submitting a transaction. But before this transaction actually gets submitted, I need to call a different web app2 that will authenticate some Knowledge Based Questions. Once successful I need to resume submisstion of transaction and control should come back to web app1..But if authentication fails control should again come back to web app1 and instead of submitin gthe transaction I need to handle it other way.

    Kindly suggest with some steps and code example. I am using java and Spring MVC.

    Thanks,
    Manish

  69. JACOB JOY says:

    I am getting an error that constructor Date is undefined.

  70. Satyabrata Mohanty says:

    Great to see you are running & accessing servlet from localhost. I succeeded in that.

    No how can I run same HelloWorld servlet on remote linux server with static IP. I have root access to remote linux machine with static IP.

    Please help!

    1. Pankaj says:

      Change localhost to the machine IP, thats it.

  71. Mo Fin says:

    Thanks for this tutorial, great stuff!

  72. Abhinav Chawan says:

    I m getting below error after running above code please help

    HTTP Status 404 – /

    1. Pankaj says:

      check the URL its hitting, 404 means resource not found.

    2. Lucian says:

      I needed to import this, wasn’t mentioned in the code

      import javax.servlet.annotation.WebInitParam;

      it worked after that

      1. Pankaj says:

        If you are using a class and it’s not imported, you will get compile time error. Your application won’t event build and deploy without fixing it, so I dont think this is the problem for Abhinav.

        Also it’s mentioned in the above code.

        1. kupi says:

          Hi friends,
          I’m trying to switchover my career from IT support to java programmer. I have very good knowledge in core java.
          I’m trying to learn jsp & servlet. But it is very much confusing. If u have any document to emplain jsp& servlet in simple manner, kinldy share..

          If u can explain jsp concepts with a demo prject, that will be very helpful for my future/career.

          Thanks,
          Kupi.

          1. Pankaj says:

            Go through the online tutorials and there are so many good books out there.

        2. Manish says:

          Yes Lucian is right , I was also facing same .
          Pankaj it’s not complaining for this at build time, may be you need to update this example.

          1. Pankaj says:

            Hi Manish,

            As mentioned in above comment, if you won’t have import for WebInitParam, then you will get compile time error, there is no way the code will compile fine.

            Also in above code, import statement is present. So I am not sure what do you mean by updating the example.

  73. Vash2007 says:

    Thanks for the quick overview. That was very helpful. I was wondering if you have another overview of how a dynamic web project can be made into a maven dynamic web project?

    1. Pankaj says:

      I think you need to create “Dynamic Web Project” first and then from the project menu, Configure> “Convert to Maven Project” option to convert it to Maven Project.

  74. Siddu says:

    Can you tell me the why GenericServlet they made as an abstract class Why can’t be interface.

  75. bagsh says:

    I savor, lead to I discovered just what I used to be looking for. You’ve ended my 4 day long hunt! God Bless you man. Have a nice day. Bye

  76. corsibu says:

    It is outdated to reference Java Enterprise as J2ee, nowdays it is common sense to use Java EE X
    where X stands for the version 5 or above(eg. Java EE 5).

    I also doubt that the annotations introduced with EJB 3.0 relate to prior versions of Java EE 😉

  77. Aditya says:

    You said HTTP is the common language between server and client and stands for Hyper Text Markup Language ???
    I am reading correct ?
    I mean it must be HTML in place of HTTP.
    Please let me know if any errors.
    By the way the article is very nice.
    Would love to read more about Apache and tomcat practical questions as well as answers to the questions such as where is init method ? what code and class is executed first when first request is received by servlet? Please post informative articles on these subjects too.
    Also allow people to download the sample code for reference.

    1. Pankaj says:

      Thanks Aditya for pointing out the type, mistakenly I wrote HTTP instead of HTML. Corrected the article and next article is about Servlets in more detail.

      Regarding downloading source code, you can easily copy paste it into Eclipse IDE. Its better for learning than just download the project and run it.

  78. Amit says:

    very nice tutorial, i was under impression that I know all about web applications but I learned something new today. I am still using servlet 2.5 but its nice to see annotations in 3.0

    looking forward for future posts, G+1 from my side. 🙂

    1. kavousi says:

      I really enjoyed it
      thanks alot

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