03 Overview

Java programs can be used in two ways :
- Stand alone EXEs
- Applets which operate only within a browser

The Java compiler creates a file that contains Java bytecodes, which in turn are interpreted
by the interpreter on each specific Java platform.

Java source code is saved in a .java text file. The compiled bytecode is saved to a . class binary file.
Source code consists entirely of classes. Program starts in a class which has a 'main' method.
Source code lines end in semi - colon

class MyClass {
      public statis void Main(String[] arguments) {
              'main statements go here
      }
}

myProgram.java (source code) --> myProgram. class (bytecode)

It is the . class file that is interpreted by the Java interpreter on a specific platform.

Java Platform consists of :
- Java Virtual Machine (interpreter)
- Java API

Java API are grouped into "packages" which contain related classes and interfaces.

A Java applet is a Java program which adheres to specific conventions that allow it
to run within a Java - enabled browser. Java applets can also be viewed in a free
program called appletviewer.

JDK - Java Development Kit from Sun
    - Java compiler
    - a few applets
    - stand - alone AppletViewer