import java.io.*;
//printing a message on the screen
//notice the format of the code
public class HelloClass
{
     public static void main (String[ ] args)
     {
          System.out.println ("Hello, Java world!");
          System.out.println ("I plan to be a Java expert!");
     }
}

Notice the format style that we will be using.  The indentations keep the code clearly visible and easy to read. 

It is possible, in Java, to write all of your code on one line -- this is called free form style.  Free form style is extremely difficult to debug at a later date and is nearly impossible for a programming team to decipher.  We will NOT be using free form style.

   if (netpay > grosspay)

   If (NetPay > GrossPay)

   IF (NETPAY > GROSSPAY)

import java.io.*;
//printing another message on the screen
//notice the commented lines
public class HelloAgainClass
{
     public static void main (String[ ] args)
     {
          System.out.println ("Hello!");  //first print
          System.out.println ("I just love this Java!");
     }
}
/*sometimes comments are longer statements that
wrap around to the next line on the screen*/

In Java, comments may be expressed in different forms.

  The comments beginning with // are single line comments.  They can appear on a line by themselves, or they may follow other lines of code.

The comments enclosed within /* and */ are used for longer comments that wrap around a line.

import java.io.*;
//notice the spacing in this code
public class HelloStillClass
{
     public static void main (String[ ] args)
     {
          System.out.println ("Java rocks!");

          System.out.println ("A real space cadet!");
     }
}

Blank lines between lines of code are also ignored.  Notice the blank line between the two print statements.

You cannot, however, embed blanks in identifiers.

The use of blanks improves readability.