Comments in Java Programming and its Use

What are Comments

In Java program Comments are portions of the code ignored by the compiler which allow the user to make simple notes in the relevant areas of the source code.

Video Explanation

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Comments in Java programming are used to provide information about lines of code. It is widely used for documenting code. There are 2 types of comments in Java programming.

• Single Line Comments - Single line comments starts with //.
• Multi-Line Comments - Multi-Line comments start with a slash asterisk /* and end with an asterisk slash */. It can occupy many lines of code. It is also known as Block Comments.

Let's see some example for more understanding.

public class Example
{
    public static void main(String[] args)
    {
        // Printing Hello World on the screen.
        System.out.println("Hello World");    // This line will print Hello World on the screen.
    }
}

Hello World

In the above program, we have used two single-line comments to explain the program. The first one is // Printing Hello World on the screen. and the second one is // This line will print Hello World on the screen.

public class Example
{
    public static void main(String[] args)
    {
        /* In this program we will learn how
        to print Hello World on the screen */
        System.out.println("Hello World");
        //System.out.println("This is a Java tutorial");
    }
}

Hello World

In the above program, we have used multi-line comments to explain what the program is all about. We can also comment out any statement that we don't want to execute in your program but want to keep it for future reference as shown above. We have commented out the statement //System.out.println("This is a Java tutorial");.