Comments in Java are special notes in the code that help explain what the code does. They are not executed by the computer and are meant for anyone reading the code. This lesson explains the types of comments you can use, why they are useful, and how to write them.

Single-Line Comments

Single-line comments start with // and extend to the end of the line. They are used to add short notes or explanations.

Syntax

// This is a single-line comment

Example

Explanation:

• The text following // is a comment.
• It is useful for explaining what a single line or a small block of code does.

Multi-Line Comments

Multi-line comments start with /* and end with */. They allow you to write comments that span several lines.

Syntax

/*
 This is a multi-line comment.
 It can span multiple lines.
*/

Example

Explanation:

• Everything between /* and */ is ignored by the computer.
• Multi-line comments are useful when you need to write detailed explanations or temporarily block out a section of code.

Documentation Comments

Documentation comments are special multi-line comments that begin with /** and end with */. They are used to describe classes, methods, and fields and can be processed by tools like Javadoc to create external documentation.

Syntax

/**
 * This is a documentation comment.
 * It can be used to describe a class or a method.
 */

Example

Explanation:

• Documentation comments help others understand your code.
• They are useful for generating reference documents that explain how your classes and methods work.

Why Use Comments?

• Improve Readability: Comments make your code easier to read by explaining what each part does, especially for someone new to the code.
• Ease Maintenance: Comments help you remember the purpose of code sections when you return to your code later, making it easier to update and fix.
• Debugging: Sometimes, you can use comments to "turn off" parts of your code when testing or debugging.
• Documentation: Documentation comments help create manuals or guides for how your code functions. This is very useful when working in a team or sharing your code with others.

Tips for Writing Good Comments

• Be Clear and Concise: Write clear explanations that a beginner can follow.
• Avoid Redundancy: Do not state the obvious. Only add comments where needed.
• Update Your Comments: Make sure comments are updated if the code changes.
• Use Proper Formatting: For documentation, follow the standard format so tools like Javadoc can generate proper documentation.

With this clear understanding of Java comments, you are now better prepared to write code that is easy to understand and maintain.