Mock Objects in Java

Java(TM) Boutique - Using Mock Objects in Java

A mock object is, as the name implies, a simulation of some real object. In Java, a mock object would typically be an implementation, with very limited functionality, of an Interface. Mock objects play a significant role in unit testing, for a number of reasons. You'd consider using a mock object for your unit test if the real object has a complex set-up, uses many system resources (like cpu power), or doesn't yet exist! If you're writing an application that uses a database, there's no need to wait for the team that develops the database modules before you start coding the rest of the application. What you need is a mock object that behaves like the database modules. If you have interfaces defined to the database modules you're ready to go. Coding with these interfaces might even bring some problems in the Interface design to the surface before the coding of the database modules has even started!

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