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Comments in Java - Single Line, Multi-Line & Documentation

Understand how to write comments in Java. Learn about single-line, multi-line, and Javadoc comments.

Why Comments?

Comments are used to explain Java code, and to make it more readable. They are ignored by the compiler.

1. Single-line Comments

Starts with two forward slashes //.

// This is a comment
System.out.println("Hello"); // This is also a comment

2. Multi-line Comments

Starts with /* and ends with */.

/* The code below will print the words Hello World
to the screen, and it is amazing */
System.out.println("Hello World");

3. Documentation Comments (Javadoc)

Starts with /** and ends with */. Used to generate API documentation.

/**
 * This method calculates the sum of two integers.
 * @param a First integer
 * @param b Second integer
 * @return Sum of a and b
 */
public int sum(int a, int b) {
    return a + b;
}

Frequently Asked Questions