The Null Object pattern is a behavioral design pattern that provides a default object as a representative of "null" in the context of design patterns.

Command pattern is a design pattern that converts a request into a standalone object, allowing the client to parametrize objects with different requests, queue a request, or log requests. The pattern involves creating a command class that encapsulates the request as an object, and passes the request to the invoker object. The invoker object then executes the command. This pattern can be useful in situations where you want to decouple the client from the receiver of the request, and where you want to provide a unified interface for undo and redo operations.

The State pattern allows an object to alter its behavior when its internal state changes, while the Strategy pattern allows an object to change its behavior based on the context it is in

A behavioral design pattern that separates an algorithm from an object structure on which it operates. The pattern allows you to define a new operation without changing the classes of the objects on which it operates.

Some of the design patterns used in the JDK library include Decorator, Mediator, State, and Strategy. These patterns are used in various classes and APIs of the Java Standard Library to provide a clean and efficient implementation of common design problems.

A Singleton class in Java can be created by declaring a private constructor and a public static method that returns the only instance of the class. This ensures that there is only one instance of the class in the JVM and that it can be easily accessed by other objects in the system.

The MVC pattern separates application logic into three distinct components, the Model, View and Controller, in order to create a flexible, reusable and scalable code structure.

The Deadly Diamond of Death is a situation in which multiple inheritance results in ambiguity and complexity in the inheritance hierarchy of a system. This can lead to difficulty in maintaining the system and understanding its behavior.

The Bridge pattern decouples an abstraction from its implementation, allowing the two to vary independently, while the Filter pattern provides a way to filter requests that pass through a set of handlers.

Prototype pattern is a design pattern that creates objects by cloning existing objects, rather than creating new instances from scratch. This pattern involves implementing a prototype interface, which is used to create a new instance of the object. The new instance is a copy of the existing object, with any changes made to the copy not affecting the original.