First Java Program

Hello world (First java program):

Java is a high level programming language and it is used to develop the robust application. Java application program is platform independent and can be run on any operating System. Writing Hello World program is very simple. To write the Hello world program you need  simple text editor like note pad and  jdk must be install in your machine for compiling and running. Hello world program is the first step of java programming  language. Be careful when you write the java code in your text pad because java is a case sensitive programming language.

  

For Example

hello world   !=(not equal to) Hello World

Write the following code into your note pad to run the Hello World program .

class HelloWorld {    public static void main(String[] args){    System.out.println("Hello World!");    } }

Save the file and Please remember the location where you save your file. In this example we have saved the file in the "C:\javatutorial\example" directory. The file name should be match the class name and to save the file give the .java extension. e.g.  HelloWorld.java
Now open the command prompt to compile the HelloWorld.java program. Go to the directory where you have saved the file ( in our case C:\javatutorial\example>) and issue the following command to compile the program:

C:\javatutorial\example>javac HelloWorld.java

javac is a compiler in the java Language. Java compiler change the programming Language into machinery language. So that the java virtual can understand it. Once the compilation is successful a new file will be created with the name HelloWorld.class.  To run the program issue the following command on command prompt:

C:\javatutorial\example>java HelloWorld

You will see the following result on the command prompt.

Hello World!

Here is the screen shot of the above steps:

In this lesson you have learned how to write and then test the Hello World! java program.

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