The Command pattern is one of the 23 design patterns introduced with the ... First, take a look at the class diagram in Figure 2. public interface Vehicle { void start(); void stop(); void ...

We discuss some of the most common design ... factory class. The Singleton Pattern restricts the instantiation of a Class and ensures that only one instance of the class exists in the Java Virtual ...

The Observable design pattern is used in many important Java APIs. One well-known example ... The Subscriber class represents the user who subscribes to the email newsletter.