Design Patterns in JAVA

Creational Design Patterns

1. Factory Pattern - provides an interface for creating objects but allows subclasses to alter the type of objects that will be created.
2. Singleton Pattern - ensures a class has only one instance and provides a global point of access to that instance.

Structural Design Patterns

1. Adapter Pattern - allows objects with incompatible interfaces to work together.
2. Facade Pattern - provides a unified interface to a set of interfaces in a subsystem.
3. Decorator Pattern - allows the behavior of an object to be extended dynamically, without the need to change its source code.

Behavioral Design Patterns

1. Command Pattern - encapsulating all the data related to command in one object.
2. Observer Pattern - defines a one-to-many dependency between objects.