Learn Java

New to java and have thirst to know what exactly all about? then you have come to the right place.
In 1991 small group of sun engineers called the 'Green Team' worked hard to come with Java.Since then it has revolutionized the world & has touched almost every aspect of software computing.

Want to built apps with cool GUI that to independent of the underlying OS?.Want to built your own website?.want to build mobile applications?or have interest in networking so that you can communicate with the computers on the network?want to incorporate security features such as cryptography,digital signatures,authentication,authorization,public key infrastructure in your build apps?
......... LIST GOES ON....

JAVA has answer to all these requirements of a developer.

If you know c & c++ then starting to learn JAVA would be easier for you.Java also incorporates the OOP(object oriented programming)concepts and has packages(you folder/directory) where you keep all your classes.Unlike c Java has both a Compiler and an Interpreter.First *.java files are converted into *.class file using javac(java compiler).These class upon execution are first sent to a class loader and then to an interpreter contained in the JVM(Java Virtual Machine).It is upto the JVM to check for any errors or runtime exceptions.After this process is complete you can see your application running.

To begin with a hello world of java----
open notepad or any text editor for that matter and type the following code >

package 1.2 //This is always the first line in any java src file
//import statements can be placed here as per the requirement

class abc //define a class of name abc
{
public static void main(String[] args)
//main function is the place from where the execution of the program commences
//args[] can be used to take inputs from the command line arguments.
{
System.out.println("Welcome to JAVA"); //would print text in " " on the console
}
}//end of class

Save this file as abc.java.As explained above compile this file using javac abc.java in cmd.If no error is shown(which is generally syntax error) then run the class file using java abc.

NOTE : Before you can use javac statement you have to set the path as the bin folder of JDK.
no For example : set path=c:\jdk1.5\bin
Also note that classpath must contain the location where your class file is saved

Here is a video tutorial :


How do you feel after successfully running your first program ---- cool amazing isn't it is a very good feeling if you are newbie to programming.

but hey never think that java can do just that there is whole lot things in the stock beyond your imagination.

Some of the key areas on which i can focus in my next post :
(besides concepts of OOP)

1. Exception Handling

2. Event Handling

3. AWT (Abstract Window toolkit) components for system dependent GUI with heavy-weight components.

4. Multiple Tasking or Multiple Threading

5. TCP/IP socket programming

6. Advanced GUI - swing,Java2D,Java3D

7. Distributed systems on network - RMI , JINI , JavaSpaces , corba, RMI IIOP(RMI + CORBA)

8. Web - Servlets , JSP(scriptlets and JavaBeans)

9. Security - Java Sandbox Security Model,Java Cryptography Extensions(JCE),Java Secure Sockets Extension(JSSE),Java Authentication and Authorization Services(JAAS)

10. Database - JDBC

11. Wireless applications - WAP(Wireless application protocol),Wireless Markup Language,i-mode , J2ME(Java 2 Micro Edition)

12. EJB to implement business logic at the enterprise level.Struts and MVC.

NOTE :
You need to have the following before you can start developing with java :

1. JDK - JAVA DEVELOPMENT KIT - for most of the programming J2SE(Java 2 Standard Edition) will do fine but for EJB etc you have to download J2EE.you can download J2SE from here

2. Any Text Editor - for example TextPad or Notepad

3. Cmd or MS-DOS

for any further genuine query/suggestions you can mail me at harshblog.query@gmail.com