Comments in Java - Optimal Use for Beginners

Understanding code is essential when you start programming. Comments are an important yet often underestimated element in code that can significantly ease your work. They not only help you later with maintaining the code but also assist other developers who work with your code. In this guide, you will learn how to add comments in Java and the different forms they take.

Key insights

• Comments improve the readability of your code.
• There are different types of comments: line-based and block comments.
• JavaDoc provides a structured way to create documentation for your classes and methods.

Using Comments in Java

In Java, you can add comments in two ways: line-based or as block comments. Below, I will explain the different types of comments and how to use them effectively.

Line-based Comments

Line-based comments are simple and direct. You start a new comment line with //. Anything that follows this symbol will be ignored by the compiler. This is particularly useful for adding short explanations for specific lines of code.

An example:

// This is a line-based comment
int a = 1; // Initialize variable a with value 1
int b = 2; // Initialize variable b with value 2

By adding comments at critical points, you gain more clarity about how your code works.

Block Comments

For extensive explanations that span multiple lines, block comments are the way to go. You start a block comment with /* and end it with */. Everything in between will be ignored by the compiler. This is especially useful when you want to comment on long explanations or even multiple lines of code.

An example:

/* This is a block comment.
Here I document the following variables:
a - is used to store the value for input.
b - is used to store the value for output.
*/
int a = 1;
int b = 2;

By using block comments, you can also easily accommodate larger explanations.

JavaDoc Comments

JavaDoc uses a special syntax to generate documentation for your classes and methods. These comments start with /** and end with */. Between these markers, you can use special tags to provide information about parameters, return values, and exceptions.

A simple example might look like this:

/** * This method adds two numbers. * * @param a the first number * @param b the second number * @return the sum of a and b */
public int add(int a, int b) { return a + b;
}

This comment shows my development environment and other developers how the method works and what they can expect from it.

Structuring Code with Comments

Comments are not only useful for communicating with other developers, but they also help in structuring your code. For example, if you have a long method with multiple responsibilities, you can use block comments to mark different sections.

// Section: Read Data
// The code for reading data will go here

// Section: Process Data // The code for processing the data will go here

// Section: Output Results // The code for outputting the results will go here

By using such comments, you achieve a clear visual separation between the different logic sections of your code.

Summary

The use of comments in Java is an essential component to make your programs readable and maintainable. There are two basic types of comments: line-based comments and block comments, as well as special JavaDoc comments for documentation. When you use comments carefully and meaningfully, not only will your code be clearer for others, but also for yourself during future modifications.