Comments in Java

In Java, comments are statements ignored by the compiler, used to make the code more readable and to provide documentation.

Comments improve code readability and help developers understand logic easily.
Java supports three types of comments: Single-line, Multi-line, and Documentation (Javadoc) comments.
Documentation comments can be used to generate API docs using Javadoc tool.

Single-line Comment

Used for small explanations. Starts with //.

// This is a single-line comment
public class Demo {
    public static void main(String[] args) {
        System.out.println("Hello World"); // Prints Hello World
    }
}

Multi-line Comment

Used when you need to write explanations spanning multiple lines. Enclosed in /* ... */.

/*
 This is a multi-line comment
 It can span across multiple lines
*/
public class MultiLineDemo {
    public static void main(String[] args) {
        System.out.println("Example with multi-line comment");
    }
}

Documentation Comment

Special type of comment used to generate documentation. Enclosed in /** ... */ and processed by Javadoc tool.

/**
 * This class demonstrates documentation comment.
 * @author ProwessApps
 * @version 1.0
 */
public class DocDemo {
    /**
     * This method adds two numbers.
     * @param a first number
     * @param b second number
     * @return sum of a and b
     */
    public int add(int a, int b) {
        return a + b;
    }
}

Notes

Single-line comments are best for short explanations.
Multi-line comments are useful for detailed descriptions.
Documentation comments can be extracted into HTML docs using javadoc.
Comments are ignored by the compiler; they do not affect program execution.

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🚀 Quick Knowledge Check

Topic: Comments | Language: Java

Q1. Which type of comment is best for multiple lines in Java?

Q2. Which tool processes Java documentation comments?

/** Example comment */

Q3. What happens if comments are placed inside code in Java?

System.out.println(10 /* comment */ + 20);

Q4. Which symbol is used for single-line comments in Java?

Q5. Which of the following is a valid documentation comment in Java?

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