Java Comments

Comments are an important part of any programming language, and Java is no exception. In Java, comments are used to provide explanations or additional information about the code. They are ignored by the compiler and are not executed as part of the program. There are two types of comments in Java: single-line comments and multi-line comments. Single-line comments start with two forward slashes (//) and continue until the end of the line, while multi-line comments start with a forward slash and an asterisk (/*) and end with an asterisk and a forward slash (*/). In this article, we will take a closer look at how to use comments in Java and explore some best practices for using them effectively in your code.

Java Comments With Example

In Java, comments are used to provide explanations or additional information about the code. They are ignored by the compiler and are not executed as part of the program. There are two types of comments in Java: single-line comments and multi-line comments.

Single-line comments start with two forward slashes (//) and continue until the end of the line. They are used to provide brief explanations or comments about a single line of code. Here is an example of a single-line comment:

// This is a single-line comment

Multi-line comments start with a forward slash and an asterisk (/*) and end with an asterisk and a forward slash (*/). They can be used to provide explanations or comments that span multiple lines. Here is an example of a multi-line comment:

/*
  This is a
  multi-line comment
*/

Comments are often used to provide explanations or additional context for code, especially when the code is complex or not self-explanatory. They can also be used to temporarily disable certain lines of code or to mark sections of code that need to be reviewed or revised.

It’s good programming practice to use comments liberally in your code to make it easier to understand and maintain. However, it’s important to keep your comments concise and relevant, and to avoid overusing them. Too many unnecessary or irrelevant comments can make your code harder to read and understand.

Here is an example of a Java program with comments:

public class Main {
  public static void main(String[] args) {
    // Declare and initialize a variable
    int x = 10;
    
    /*
      Calculate the result of
      the expression and print it
    */
    int result = 2 * x + 1;
    System.out.println(result);
  }
}

In this example, we have a single-line comment that explains the purpose of the x variable and a multi-line comment that explains the purpose of the result variable and the following System.out.println statement.

Types Of Java Comments

There are two types of comments in Java: single-line comments and multi-line comments.

1. single-line comments
2. multi-line comments

Single-line comments

Single-line comments start with two forward slashes (//) and continue until the end of the line. They are used to provide brief explanations or comments about a single line of code. Here is an example of a single-line comment:

// This is a single-line comment
int x = 10; // This is also a single-line comment

Multi-line comments

Multi-line comments start with a forward slash and an asterisk (/*) and end with an asterisk and a forward slash (*/). They can be used to provide explanations or comments that span multiple lines. Here is an example of a multi-line comment:

/*
  This is a
  multi-line comment
*/
int x = 10; /* This is also a multi-line comment, even though it only spans one line */

It’s important to note that comments cannot be nested in Java. This means that you cannot include a multi-line comment inside another multi-line comment or a single-line comment inside a multi-line comment.

Here is an example of a Java program that uses both types of comments:

public class Main {
  public static void main(String[] args) {
    // Declare and initialize a variable
    int x = 10;
    
    /*
      Calculate the result of
      the expression and print it
    */
    int result = 2 * x + 1;
    System.out.println(result); // Print the result
  }
}

In this example, we have a single-line comment that explains the purpose of the x variable and a multi-line comment that explains the purpose of the result variable and the following System.out.println statement.