Comments

Fundamental Programming Standards

• 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.

Comments

• 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