Learn java Hello World

Here is a program which prints Hello World!.

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

The first line is a syntax of defining a class called HelloWorld.

public class HelloWorld {

The next line is the main method to be able to run program.

public static void main(String[] args) {

• public anyone can access it.
• static anyone can use or call this method without creating an instance of the class.
• void method doesn't return any value.
• main name of the method.
• String[] args is method arguments and it is an array of string. The argument stores the value of parameters if the program is run with any parameter.

The next line is to print Hello World! in the program.

System.out.println("Hello World!");

• System is the System class contains several useful class fields and methods.
• out is a static method of class System and a "standard" output stream corresponds to display output in the program.
• println is to print a String and then terminate a line.

An example with Eclipse: