Hiding Code in From the Compiler

You can hide code from the compiler by commenting out the code.

Code comments are fragments that the compiler will not process.

You can comment out lines of code using the // symbols or enclose a specific fragment of text or code using /* */.

Why do We Need Comments?

Comments are notes in the code that are ignored by the computer but help explain what the code does. They make programs easier to understand and maintain, and can also be used to temporarily disable parts of the code for testing or debugging.

You saw an example of commenting in the previous chapter, where a comment was placed where the code was supposed to go.

Here's another example of how to use comments:

Main.java


              123456789
            
package com.example;

public class Main {
    public static void main(String[] args) {
        System.out.println("Message 1");
        // System.out.println("Message 2");
	    System.out.println("Message 3");
    }
}

Only the first and third messages will be displayed here because the second part is commented out, so the compiler ignores it.

Now, let's take a look at an example of multi-line code commenting:

Main.java


              123456789
            
package com.example;

public class Main {
    public static void main(String[] args) {
        /* System.out.println("Message 1");
        System.out.println("Message 2"); */
        System.out.println("Message 3");
    }
}

As you can see, only the third message is displayed in the console because the first and second ones are commented out.

Task

Swipe to start coding

Your task is to identify the error and comment out the code fragment that contains it.

Solution

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 7

single

Ask AI

Ask anything or try one of the suggested questions to begin our chat

Suggested prompts:

Can you explain the difference between single-line and multi-line comments in Java?

Why is it important to use comments in code?

Can you show more examples of when to use comments in Java?

Swipe to show menu

Hiding Code in From the Compiler

You can hide code from the compiler by commenting out the code.

Code comments are fragments that the compiler will not process.

You can comment out lines of code using the // symbols or enclose a specific fragment of text or code using /* */.

Why do We Need Comments?

You saw an example of commenting in the previous chapter, where a comment was placed where the code was supposed to go.

Here's another example of how to use comments:

Main.java


              123456789
            
package com.example;

public class Main {
    public static void main(String[] args) {
        System.out.println("Message 1");
        // System.out.println("Message 2");
	    System.out.println("Message 3");
    }
}

Only the first and third messages will be displayed here because the second part is commented out, so the compiler ignores it.

Now, let's take a look at an example of multi-line code commenting:

Main.java


              123456789
            
package com.example;

public class Main {
    public static void main(String[] args) {
        /* System.out.println("Message 1");
        System.out.println("Message 2"); */
        System.out.println("Message 3");
    }
}

As you can see, only the third message is displayed in the console because the first and second ones are commented out.

Task

Swipe to start coding

Your task is to identify the error and comment out the code fragment that contains it.

Solution

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 7

single