• Okay, so now let's look at the rest of the Test class because the Test class is pretty special. The Test class is actually a very small Java Application that can be compiled and executed!

• Here is the code again...

  public class Test
    {
    public static void main(String[] args)
      {
      Announcer a = new Announcer();
      a.printAnnouncement();
      }
    }
  

• So you should already be comfortable with the definition of the class from the last section. You should also be familiar with the contents of the main() method since we just discussed it. But what is the main() method and why is there no constructor for Test?

• Well, the main() method is a very special method because it works without an instantiation of the class. It does this because the main() method is static. static is a keyword which, when applied to classes means that no instantiation is necessary in order to run it.

• Notice also that the main method may take an array of strings as arguments. This is used so that we can pass information to our application from the command line if we want. However, in this case we won't be passing any arguments.

Compiling an Application

• It is very easy to compile your application once you have installed and configured your JDK. You simply go to the directory in which you have saved your .java file and use javac to compile it into bytecode using the command:

  javac filename.java
  (or sometimes javac *.java to compile all java files in one directory)

Running an Application

• Once your code is compiled, you can execute the application using the java virtual machine. To do so, you type the following in the same directory:

  java filename

• Try it out by compiling and running the Test application. Don't forget that you have to make two .java files. One will be Annoucner.java and the other will be Test.java. To make your job quicker, you can click here to copy the two java files.

It Didn't Work!

• Okay, so since these are computers we are dealing with, it is possible that you had some trouble compiling and executing your test case. Here are a few possible solutions.

java Test

return _announcement;