Comments are an integral part of java programming language, providing a means for developers to add explanatory notes, annotations, or reminders within their code. In Java, comments serve as essential documentation tools, enhancing code readability and facilitating collaboration among developers. This tutorial will guide you through the various aspects of comments in Java, covering different types of comments, best practices, and their significance in the software development process.
Comments in java are ignored by java compiler and interpreter. We can add comments anywhere and any number of times in our java program.
Why Use Comments?
- Documentation : Comments provide explanations for sections of code, making it easier for developers to understand the purpose and functionality of different components.
- Debugging : Comments can be used to temporarily exclude or comment out sections of code during debugging, allowing developers to isolate issues.
- Collaboration : Comments facilitate collaboration among team members by conveying information about code logic, design decisions, or potential improvements.
- Code Maintenance : Comments assist in maintaining and updating code over time, especially when multiple developers are involved in a project.
Types of Comments in Java
Java supports three kinds of comments:
- Single Line Comments.
- Multi Line Comments.
- Documentation Comments.
Single Line Comments
- Single line comment starts with “//” symbol and till end of the line.
- It is used to comment only one line.
- Everything on the line after // is ignored by compiler.
// A method to calculate area of circleor
int sum; // Variable to store total marks
package com.tcc.java.tutorial;
public class HelloWorld{
public static void main(String args[]){
// prints Hello World
System.out.println("Hello World");
}
}
Output
Hello World
Multi Line Comments
- Multi line comments in Java start with /* and end with */. Everything between /* and */ is ignored by compiler.
- Multi line comment is used to add a comment spanning more than one line.
- Nesting of multi-line comments is not allowed.
/* This method takes radius of a circle as input argument and returns the area of circle */
package com.tcc.java.tutorial;
/*
First Java program to print "Hello World"
String on screen
*/
public class HelloWorld{
public static void main(String args[]){
System.out.println("Hello World");
}
}
Output
Hello World
Documentation Comment in Java
- Java documentation comment starts with /** and ends with */.
- It is used by JDK javadoc to automatically generate documentation.
- Java doc is a tool in JDK, it automatically generates documentation in HTML format by parsing documentation comment in java code.
- Javadoc recognize varius tags like @author, @param, @return etc.
/** * This method takes radius of a circle as input * argument and returns the area of circle * @author John */
package com.tcc.java.tutorial;
/**
* First Java program to print "Hello World"
* @author John
*/
public class HelloWorld{
public static void main(String args[]){
System.out.println("Hello World");
}
}
Output
Hello World
- Write Javadoc Comments : Follow the Javadoc syntax for comments, including tags such as @param, @return, and others. Javadoc comments should precede the class, method, or field they are documenting.
- Run the Javadoc Tool : Open a terminal or command prompt and navigate to the directory containing your Java source files. Use the following command to generate Javadoc documentation "javadoc YourClass.java". Replace YourClass.java with the name of the Java file you want to document. The Javadoc tool will process the source file and generate HTML documentation.
- View the Generated Documentation : Once the Javadoc tool completes its processing, it will create a set of HTML files containing the documentation. Open the index.html file in a web browser to view the generated documentation.
Best Practices for Using Comments
- Be Concise and Clear : Write comments that are concise and to the point. Avoid unnecessary details but provide enough information for others (or yourself) to understand the purpose of the code.
- Update Comments Alongside Code : As you modify your code, remember to update the associated comments. Outdated comments can mislead developers and lead to confusion.
- Avoid Redundant Comments : Avoid commenting the obvious or restating what is already evident from the code itself. Redundant comments can clutter the code and decrease readability.
- Use Javadoc for Public API : For classes, methods, and fields that form part of your public API, use Javadoc comments extensively. This practice helps generate comprehensive documentation for users of your code.
- Comment Complex Algorithms : When dealing with complex algorithms or non-trivial logic, provide detailed comments to guide readers through the code. Explain the purpose of each step and any critical decision points.
Conclusion: Harnessing the Power of Comments in Java
In conclusion, comments in Java play a pivotal role in enhancing code readability, facilitating collaboration, and providing valuable documentation. By adhering to best practices, choosing the appropriate type of comment, and leveraging Javadoc for public APIs, developers can ensure that their code remains clear, maintainable, and accessible to others.
As you continue your journey in Java development, consider comments not just as annotations but as a means to communicate with your fellow developers, including your future self. A well-commented codebase becomes a valuable asset, easing the learning curve for new team members and contributing to the long-term maintainability of your projects.