Introduction - Java Concepts - page 22

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1.6 Compiling a Simple Program

You are now ready to write and run your first Java program. The traditional choice for
the very first program in a new programming language is a program that displays a
simple greeting: ȒHello, World!ȓ. Let us follow that tradition. Here is the ȒHello,
World!ȓ program in Java.

ch01/hello/HelloPrinter.java

1 public class HelloPrinter
2{
3 public static void main(String[] args)
4 {
5// Display a greeting in the console window
6
7 System.out.println ( ÐHello, World!Ñ );
8 }
9}

Output

Hello, World!

We will examine this program in a minute. For now, you should make a new program
file and call it HelloPrinter.java . Enter the program instructions and compile
and run the program, following the procedure that is appropriate for your compiler.

Java is case sensitive. You must enter upper- and lowercase letters exactly as they
appear in the program listing. You cannot type MAIN or PrintLn . If you are not
careful, you will run into problemsȌsee Common Error 1.2 .

Java is case sensitive. You must be careful about distinguishing between upper- and
lowercase letters.

On the other hand, Java has free-form layout. You can use any number of spaces and
line breaks to separate words. You can cram as many words as possible into each line,

public class HelloPrinter{public static void
main(String[]