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What is an Intent?

inam — Wed, 23 Dec 2009 06:09:08 +0000

An intent is an asynchronous message used to activate an Andriod Application Components like Activity, Service and broadcast receiver, content providers are not activated by intents but by receiving a request from ContentResolver.

To activate an Activity an intent object with information of action being requested and URI of the data to be acted upon is passed to Context.startActivity() or Activity.startActivityForResult().

A service can be passed by passing an intent object to Context.startService(). To establish an ongoing connection between the calling component and a target service Context.bindService() is called by passing an intent object.

Similarly and intent object is passed to Context.sendBroadcast(), Context.sendOrderedBroadcast(), or Context.sendStickyBroadcast() to activate a service.

Tutorial: Creating Java Web Application

ali — Mon, 21 Dec 2009 18:41:36 +0000

In this tutorial you will learn how to create a simple Hello World Java web application. The application will not use any IDE and will solely depend on what JDK provides.

So, let start with our first java hello world web application.

Pre-Requisites

1- Download JDK from here. Latest JDK version at the time of writing this tutorial is 6.

2- Download and install/unzip Apache Tomcat web server (zip or tar for Linux or installer) from here

Set up Java environment on your machine

Please refer to Install And Configure JDK On Windows

Set up Apache Tomcat environment on your machine

Please refer to Set Up Apache Tomcat On Windows

Now your JDK and Tomcat is setup. We will start developing our web application. This will be a very simple web application in which only one JSP will be created and it will print some text in browser.

Lets get started.

1- Create a folder Helloworld anywhere on your machine

2- Create a JSP file helloworld.jsp under this folder.

3- Put the following code in helloworld.jsp

 
 

  
    </span></a></span>Hello world<span style="color: #009900;"><span style="color: #000000; font-weight: bold;">
  
 
  
Hello World!!!

4- Create folder Helloworld/WEB-INF

5- Create a file web.xml in WEB-INF and put the following code in this file

 
 
 version="2.5" xsi:schemaLocation="
http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
 
>
>helloworld.jsp>
>
>

6- That’s it. We are done with the coding part. Now copy the entire Helloworld folder and put it in /webapps

7- Start tomcat server, /bin/startup.bat

8- Open your browser, and access the following URL http://localhost:8080/Helloworld

Enjoy!

Set Up Apache Tomcat On Windows

ali — Sun, 20 Dec 2009 20:17:51 +0000

1- Download latest Apache Tomcat from here. You can download a zip or a tar for Linux or an installer package.

2- Unzip/ install tomcat at a proper place; say in C:/tomcat directory

Set up environment variables

1- To make tomcat run JAVA_HOME environment must be set. If you already have not done this then refer to other tutorial Install And Configure JDK On Windows and set the java variables

2- Right click My Computer click Properties and choose Advance tab

3- Press Environment Variables button

4- Press New under System variables

5- Press New and provide CATALINA_HOME as variable name and path to tomcat home directory as its value

6- Edit path variable and append path up to tomcat bin directory

7- Open command prompt, write startup and press enter. Tomcat will start running

Install And Configure JDK On Windows

ali — Sun, 20 Dec 2009 19:48:10 +0000

First download JDK from here. I am using JDK 6 for this tutorial

1- Run the JDK setup and install Java on your machine

2- On windows right click My Computer and click Properties

3- Choose Advance tab and click on Environment Variables button

4- Under System variable press New button

5- Provide JAVA_HOME variable in Variable name field and your JDK Home path in Variable value

6- Find Path variable under System variables and press Edit button. Append path up to JDK bin directory and press OK.

To check whether you JDK is setup properly open command prompt and write following command on console

> java –version

You will get output similar to the following image.

Tutorial: Java/JSP Hello World Web Application in Eclipse

ali — Sun, 20 Dec 2009 12:15:08 +0000

Pre-Requisites

Eclipse : I am using Eclipse 3.4 (Ganymede) for this application. You can download the latest version from here
Tomcat : download from here

Level: beginners

This application is for newbie how want to start java web development. In this application we will create a web application in Eclipse platform and the application will be deployed on Tomcat web server. This application will only show some output on the JSP page.

Lets start with our application

1- Open Eclipse

2- Go to New > Other

3- Select Dynamic Web Project

4- Provide a project name and press Finish

5- Following project hierarchy will be created by Eclipse

6- create a package jsp under WebContent. Right click WebContent New > Folder

7- Provide a name to the folder and press Finish

8- Create a new jsp page. Right click jsp folder New > Other and select JSP and press Next

9- Provide JSP a name and press Finish

10- Put following code in JSP

 
 
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">


"Content-Type" content="text/html; charset=ISO-8859-1">
Insert title here

 
 Hello World !!!

11- The other important file is web.xml. Put the following code in web.xml

 
 
 id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
 http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
 
 version="1.0" encoding="UTF-8"?>
    >Helloworld>
    >
        >/jsp/helloworld.jsp>
    >
>

12- Now we have to configure Tomcat Web Server. Go to Window > Preferences > Server > Runtime Environment and press Add.

13- On the next screen press Apache > Apache Tomcat v6.0, press Next

14- On the next screen Browse to the Apache tomcat home directory and press Finish and then OK.

15- Now its time to run the project. Right click the project > Run As > Run on Server. Press Finish if any other options appear.

16- Fire up your browser and provide the following URL http://localhost:8080/Helloworld/ and you will see something similar to the following output.

That’s it, we are done with our first JSP web application.

Downloads

Download the full project from here

Enjoy!