Java Comments

Java Comments

Comments can be used to explain Java code, and to make it more readable. It can also be used to prevent execution when testing alternative code.

1.     Single line comments

2.     Multiple line comments

3.     Documentation comments

Single line comments

Single-line comments start with two forward slashes (//).

Any text between // and the end of the line is ignored by Java (will not be executed).

This example uses a single-line comment before a line of code:

Example

// This is a comment

System.out.println(“Hello World”);

This example uses a single-line comment at the end of a line of code:

Example

System.out.println(“Hello World”); // This is a comment

Java Multi-line Comments

Multi-line comments start with /* and ends with */

Any text between /* and */ will be ignored by Java.

This example uses a multi-line comment (a comment block) to explain the code:

Example

/* The code below will print the words Hello World

to the screen, and it is amazing */

System.out.println(“Hello World”);

 

Single or multi-line comments?

It is up to you which you want to use. Normally, we use // for short comments, and /* */ for longer.

 

Java Documentation Comments

The documentation comment is used to create documentation API. To create documentation API, you need to use Javadoc tool.

It is used to produce an HTML file that documents your program. It begins with a /** and ends with a */.

/**

* <h1>Hello, World!</h1>

*This will simply displays “Hello World!”

* <p>

* <b>Note:</b> Giving proper comments in your program makes it more user friendly and

* it is assumed as a high quality code.

*

*

* @author abcd

* @version 1.1

* @since yyyy-mm-dd

*/

System.out.println(“Hello World”);