Comments 

• Just as we saw in Perl, Java uses the standard syntax for defining the parts of a program. For example, all commands are ended with a semicolon(;) 

        int i = 5;

• Similarly, all blocks of code are defined by curly braces such as in the following example:

if (i <10)
  {
  System.out.println("i is less than 5);
  }

• This type of programming should be very familiar for you from yesterday.

• Just as you could use the number sign (#) to let the Perl interpreter know that a line in the code was a comment, you can specify comments in Java. 
• Actually, there are several ways to denote comments in Java. 
• For single line comments, you can use the "//" notation. For example, consider the following code: 

                // Initialize variables...
int age = 28;   // Declare and initialize age

• Single line comments can be defined on the same line as your code or on their own line 
• To specify multiline comments, however, you will use the "/*" and "*/" combination such as in the following example: 

/*
This is a sample class which is used to demonstrate
the use of multi-line comments.  it was written by
Selena Sol for the Web Programming Tutorial
*/

        // Define an Example class with a single
        // main() method which will print out
        // "Hello Cyberspace!" to standard output.

public class Example
  {
  public static void main(String[] args)
    {
    System.out.println("Hello Cyberspace!");
    }
  }

• As you can see, if you use the "//" notation and your comment spans multiple lines, you must begin each new line with a "//" combination. 
• Finally, if you are writing comments which should be included as part of a javadoc document, you should use the "/**" "*/" combination such as in the following example: 

/*
This is a sample class which is used to demonstrate
the use of multi-line comments.  it was written by
Selena Sol for the Web Programming Tutorial.  This comment
does not appear in the java documentation
*/

        /** 
        Define an Example class with a single
        main() method which will print out
        "Hello Cyberspace!" to standard output.
        This comment appears in the javadoc.
        */

public class Example
  {
  public static void main(String[] args)
    {
    System.out.println("Hello Cyberspace!");
    }
  }

Additional Resources:

• Learning to Write Java 
• Introducing Java (TM) - Your First Applet 
• Java FAQs 
• Java Software 
• java.sun.com 
• Sun Microsystems

Setting Your Development Environment
Table of Contents
Printing to Standard Output