Q1. What is the difference between the Decorator pattern and Proxy pattern?

A: A Decorator adds behavior to the object that it decorates at runtime, while a Proxy controls access to an object. The relationship between Proxy and RealSubject is at compile time and not dynamic.

Q2. What are the disadvantages of the Proxy pattern?

A: The Proxy pattern can increase the response time. For instance, if the Proxy is not well-architectured or has some performance issues, it can add to the response time of RealSubject. Generally, it all depends on how well a Proxy is written.

Q3. Can the client access RealSubject independently?

A: Yes, but there are certain advantages that Proxies provide such as virtual, remote, and others, so it's advantageous to use the Proxy pattern.

Q4. Does the Proxy add any functionality of its own?

A: A Proxy can add additional functionality to RealSubject without changing the object's code. Proxy and RealSubject would implement the same interface.