It is important for developers to test code that they write to insurethat they are meeting the specifications for their application. Oftentest code is built in a separate program which loads and tests aparticular class. Instead, you can include test code directly insideyour class and place it in a “main” method.
When you run a Java program from the command line:
java ApplicationStartingClass
you supply the name of the class that contains the start up code. Javaexecute a specific method in that class, the “main” method:
public class ApplicationStartingClass{ public static void main( String[] args ) { . . . }}
You can use this feature of Java to embed test code inside each of theclasses that you write. If you are working developing the class Person,you can include a main method in the class, even though it will never becalled during normal use.
public class Person{ . . . public static void main( String[] args ) { // include test code which exercises the class Person }}
When you need to test your class, you simply run the class from thecommand line:
java Person