Java Examples

Here are a bunch of examples that may help you with the Object Oriented Programming course, or with programming Java in general. Some examples are simpler than others, but I thought it would be useful to also show some more complete programs which combine the techniques shown in the simpler examples. If you miss an example, feel free to contact me or create an Issue.

Examples

Action example

This example demonstrates how to build a simple menu bar using actions based on AbstractAction in anonymous classes.

Drawing example

This example shows how to use and override protected void paintComponent(Graphics g) to paint your own component (or more specifically, JPanel).

Observer example

This demo shows how you can use the Observer interface and Observable class.

Counter example

This larger demo combines the Action and Observer examples and is the tiniest complete working program example of the MVC pattern I could remember.

Grid example

This is more of a fun project to be honest, it is a demonstration of how to use the code from the Drawing Example combined with the KeyListener interface to create a simple game which stores its data in a grid.

Method chaining example

A simple example to show what really happens when you write x.getA().getB().getC() using a rich man.

Undo Manager example

This program contains a model that has an UndoManager which it uses to store all the edits made. The example also demonstrates how to keep all the places where the data is used up to date, and is therefore also quite a nice example of the Observable pattern.