Java Documentation

There are three kinds of comments in the Java language − 

Javadoc is a tool that comes with JDK and is used to generate Java code documentation from Java source code in HTML format, which needs predefined format documentation. 

Following is a straightforward instance/example where Java multi-line comments are the lines inside /* .... */. Similarly, Java's single-line comment is the line that precedes //. 

Example: 

/* 
* The MyHelloWorldProgramprogram is a program  
* that simply displays "My name is John!" to the standard 
* output. 
* 
*/ 
public class MyHelloWorldProgram { 
public static void main(String[] args){ 
// Prints My name is John! on standard output. 
      System.out.println("My name is John!"); 
   } 
} 

Inside the description section, you can include necessary HTML tags. For example, < h1> .... </h1 > for heading is used in the following example and < p > is used to create paragraph break − 

Example: 

/** 
* <h 1> Hello, World! </h 1> 
* The MyHelloWorldProgramprogram implements an application  
* that simply displays "My name is John!" to the output. 
* <p> 
* Giving proper comments in your program makes it more 
* user friendly and it is assumed as a high quality code. 
* </p> 
*/ 
public class MyHelloWorldProgram { 
public static void main(String[] args){ 
/* Prints My name is John!"! on standard output. 
      System.out.println("My name is John!"); 
   } 
} 

The javadoc tool acknowledges the tags below − 

Example: 

The program that follows utilizes a few of the significant tags accessible to comments for the documentation. Based on your demands, you can use other tags also. 

The MultiplyNum class documentation will be produced in the MultiplyNum.html i.e. a HTML file, but at the same time a master file with an index.html name will also be created. 

import java.io.*; 
/** 
* <h 1>Multiply 2 Numbers!</h 1> 
* The MultiplyNumprogram implements an application that 
* simply multiply two given integer numbers and Prints 
* the output on the screen. 
* <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  John Walter 
* @version 2.0 
* @since   2019-03-16 
*/ 
public class MultiplyNum{ 
/** 
   * This method is used to multiply two integers. This is 
   * a the simplest form of a class method, just to 
   * show the usage of various javadoc Tags. 
   * @param numA This is the first paramter to multiplyNum  
   * method 
   * @param numB  This is the second parameter to multiplyNum          method 
   * @return int This returns multiplication of numA and numB. 
   */ 
public int multiplyNum (int numA,int numB){ 
return numA * numB; 
} 
/** 
   * This is the main method which makes use of addNum method. 
   * @param args Unused. 
   * @return Nothing. 
   * @exception IOException On input error. 
   * @see IOException 
   */ 
public static void main(String args[])throws IOException{ 
MultiplyNum obj =new MultiplyNum(); 
int result = obj. multiplyNum(10,20); 
System.out.println("Multiplication of 10 and 20 is :"+ result); 
} 
} 

Now, process the above MultiplyNum.java file using javadoc utility as follows – 

$ javadoc MultiplyNum.java