Introduction to Java!

"JAVA was developed by Sun Microsystems Inc in 1991, later acquired by Oracle Corporation. It was developed by James Gosling and Patrick Naughton. It is a simple programming language. Writing, compiling and debugging a program is easy in java. It helps to create modular programs and reusable code."

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Welcome to Java.

In this tutorial, you will learn to write "Hello World" program in Java.

A "Hello, World!" is a simple program that outputs Hello, World! on the screen. Since it's a very simple program, it's often used to introduce a new programming language to a newbie.

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

Output

Hello, World!

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So how it is works?

• //Your First Program

In Java, any line starting with // is a comment.
Comments are intended for users reading the code to understand the intent and functionality of the program. It is completely ignored by the Java compiler.

• public class HelloWorld{...}

In Java, every application begins with a class definition. It is depends on your file name, for example your file name will be Hello.java so the class has to be called "Hello".

public class Hello {
    // Class Definition
}

• public static void main(String[] args) {...}

This is the main method. Every application in Java must contain the main method. The Java compiler starts executing the code from the main method.

public static void main(String[] args) {
    // Main Method
}

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

The code above is a print statement. It prints the text Hello, World! to standard output (your screen).