Magic with Java Program

                                       Java

It’s a programming language just like c and c++.But differs in terms of OOP’s concepts ….java is completely object oriented…

Object oriented means you cannot use main () function directly as you use in c/c++ ….c++ also follow OOP’s but partially that is why you can use main () function as well as class both.

Java is most popular programming language used in almost every thing.

HISTORY ABOUT JAVA:

DEVELOPED BY: James Gosling at Sun Microsystems in 1990.

OLD NAME: Oak.

RE-NAMED: Java in 1995.

HOW TO INSTALL AND USE:

You can download the latest version java from website of java that you can search with the help of www.Google.com  .

• Remember about your operating system if you are using Windows Os like Windows Xp /Windows7/8 than download java for Windows . . .if you are using any other than download according to your operating system.

As you complete the Download Run the setup….

Then follow the instructions…………

After you complete the Installation :

Go to the Directory where you install java and copy address from address bar at BIN

Ex. “C:\Program Files\Java\jdk1.7.0\bin”  after copying that address..

·      

   Right click on My Computer

·         >Properties

·         >Advanced system settings

·         >Environment Variables

·         >new

·         >in Variable name :you can use any variable like java, path  etc.

·         >in Variable Value: just past the address  “C:\Program Files\Java\jdk1.7.0\bin”

·         >ok

·         >ok

·         >ok

Now go to command prompt and type  java   you get a lots of information about java that means your system is ready for use…..

EDITOR FOR JAVA:

There are lots of java editor available…

Like:

1. Jcreator
2. Editplus
3. Netbeans 
4. Notepad++
5. Eclipse IDE

But the simplest one are:

Notepad or command prompt editor

1.  If you are using Note pad than use extension of file as “your_file_name.java”
2.  You can also use command prompt editor

For that :

• Go to your java installed directory in command prompt

Ex.

C:\Program Files\Java\jdk1.7.0\bin

Then type edit “your_file_name.java”

C:\Program Files\Java\jdk1.7.0\bin edit hello.java

For Working with command prompt you need to know about few basic commands

Commands of DOS(Disk Operating System)

cd.. –for change the root directory

Ex.

C:\Program Files\Java\jdk1.7.0\bin> cd..

Out put

C:\Program Files\Java\jdk1.7.0>

cd/ -for jump to

Ex.

C:\Program Files\Java\jdk1.7.0\bin> cd/

Out put

C:\>

Drive_name:   -for changing working Drive

C:\Program Files\Java\jdk1.7.0\bin> d:

Out put

D:\>

cls   -command for clear screen to clear your command prompt screen.

How to Execute/Run java program:

Java programs Executed in two steps Interpreted and then run/executed ….

For interpreter java program –

C:\Program Files\Java\jdk1.7.0\bin>javac “filename.java”

For run-

C:\Program Files\Java\jdk1.7.0\bin>java classname

Note:- Here the class name is the name of class that you are used in file

Example:

//To print hello to java  file name- hello.java

class hello

{

public static void main(String a[])

{

System.out.println(“hello”);

}

}

Explanation of program:

C:\Program Files\Java\jdk1.7.0\bin>javac hello.java

Note: if any kind of error present in your program than, that is shown as error. If not than it return to the current directory.

C:\Program Files\Java\jdk1.7.0\bin>java hello

Out put will be: hello

Points to remember:-

• ·         Try to use same name for file name and class name. You can use different name also ,but careful while execution/running the program
• ·         Public static void main---all are in small letter But String uses Capital ‘S’ similarly in System.out.println()
• ·         You can use System.out.println() or print() :- println() print with new line while print() print with same line.