Learning JAVA for beginners

Running Application

Open command prompt go in the drive (where you save your notepad file)

Then type__

javac Hellojava.java

now run your application__

java Hellojava

a message will seem "Hello ! Java"

What you did !

Line of code is a blank line, which as you might imagine, does nothing.

Following that is the beginning of your program class definition:

public class HelloWorld {

You must define a class in every Java program. Basically, a class is a group of functions

and characteristics in Java code that can be reused. The public keyword,

used as a modifier that describes other classes' access to this class, is not

required, but it is a good idea to use it anyway. This way you will start off with

good coding habits. It is not necessary at this point to fully understand the public

keyword.

The same goes for the class keyword. It is used to identify Hellojava as a class.

The open brace denotes the beginning of the contents of your class definition

and the corresponding closing brace (the last line of the program) denotes the

end of the class definition. To sum it up, this line of code starts a Java program

called Hellojava, and all the code within the braces makes up its guts.

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The next line of code starts the main() method definition.

public static void main(String args[]) {

Methods are groups of statements that are executed by your computer when

instructed to do so. You learn about methods in Chapter 5. For now, it is important

that you know that the main() method actually drives Java applications. It is

the first place the Java VM looks when you run your application. The group of

statements within this method, collectively called a block statement, is defined

within its own set of braces. Within the braces of this method, you define a list

of steps you want the computer to do when running your program.

The one statement inside the main() method, which is your next line of code,

instructs your computer to say hello to the world.

System.out.println("Hello, world!");

This is actually a call to a method that handles your system's standard output. It

prints one line to the screen and adds a carriage return. You can refer to the Java

API documentation for classes System and PrintStream for more detailed information

Congrats ! now you know the syntax and knowledge about JAVA

Thanks

Nikhil Kumar

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