Today we will begin in earnest our trek through the complexities of java.

We will be exploring what it means for java to be an Object Oriented Program (OOP).

Our work will involve experimentation with the contents of these 4 files, so that we can beging to gain an understanding as to what they do and why they do it.

Create a folder called "April14". Please click each link and download each file into this directory. Make sure each is compiled, and see what happens when they are run.

http://www.roseindia.net/java/master-java/Mainclass.java

http://www.roseindia.net/java/master-java/inherit.java

http://www.roseindia.net/java/master-java/polyone.java

http://www.roseindia.net/java/master-java/polytwo.java

Take note: In the Java language, when you execute a class with the Java interpreter, the runtime system starts by calling the class's main() method. The main() method then calls all the other methods required to run your application. You can identify the main methods here by looking for public static void main(String[] args){ .

• public indicates that the main() method can be called by any object.
• static indicates that the main() method is a class method.
• void indicates that the main() method has no return value.

More of this in class.