The latest project I worked on in college is a calculator created using TDD (Test Driven Development). It’s based on a project taken from Google’s Testing Blog located here. It’s a fully functioning calculator similar to the one available with Windows.

I’ve added it to a .jar file which you can download below and run by double-clicking it like a normal application after extracting it from the .zip archive. Extracting the .jar file afterwards will show you my source code.

calculator.jar

I haven’t added any Java projects in a while. This first one is a text alerts project where a match attender notifies subscribers about any updates from a certain match.

textAlerts.zip

This second one is a basic application with a user interface using a MiGLayout and Swing. It will run by double-clicking the extracted file.

migapp.zip

Both projects will only work if you have Java installed and the first one will only work if you run it in either Eclipse or Command Prompt.

A constant in java is a variable with a pre-defined value. To declare a variable as a constant, use the final modifier:

public static final int VARIABLENAME = 0;

VARIABLENAME can’t ever be assigned to a different value.

The full name for this declaration is an enumerated constant.

In java, a class is a (possibly partial) implementation of a type. There are 3 different classes; concrete classes, abstract classes and interface classes. Concrete is a fully complete class, abstract is a semi-completed class and an interface is an incomplete class. An interface is fully abstract with no method implementation. The reason for an abstract class is because the implementation is too general at a high level.

Type: List of responsibilities (method headers)

Class: Type and implementation (instance variables and method bodies)

In java there is single implementation inheritance, but multiple interface inheritance i.e. you can only have one class listed after extends, but you can have a comma-separated list after interface.