Wouldn’t it be nice if all Java classes that you use, including your own, lived up to their promises? In fact, wouldn’t it be nice if you actually knew exactly what a given class promises? If you ...

Object-oriented systems are usually partitioned into layers of related responsibilities and only dependencies in one direction are allowed, from higher layers (more specific, less reusable) to lower ...

Imagine you are an expert object-oriented Java developer who meticulously crafts code the way an artist cares for their masterpiece. You believe clean code is an absolute necessity. Classes with clear ...

The Observable design pattern is used in many important Java APIs. One well-known example is a JButton that uses the ActionListener API to execute an action. In this example, we have an ActionListener ...

Depreciation is the decline in monetary value an asset will experience over the course of its useful life. Knowing the depreciation value of certain items allows companies to accurately report ...