What is the difference between Proxy and Decorator patterns in software design?

The Proxy and Decorator patterns are similar in that both use a wrapper object to extend functionality, but they have different purposes:

• Proxy controls access to another object, and can perform additional actions before or after accessing the real object (e.g., lazy initialization, permission checks, caching).

• Decorator dynamically adds new responsibilities to an object, extending its behavior without modifying the original class.

Example:

• Proxy can check if a user has permission to call a method.
• Decorator can add logging or formatting of the result.

Thus, Proxy focuses on access control, while Decorator focuses on extending functionality.