What design patterns do you know?

Of course. I will list the main design patterns in Java:

Creational:

• Singleton: Ensures that a class has only one instance and provides a global point of access to it.
• Factory Method: Defines an interface for creating an object but allows subclasses to decide which class to instantiate.
• Abstract Factory: Provides an interface for creating families of related or dependent objects without specifying their concrete classes.
• Builder: Separates the construction of a complex object from its representation so that the same construction process can create different representations.
• Prototype: Defines an interface for creating copies of objects through cloning.

Structural:

• Adapter: Converts the interface of a class into another interface clients expect.
• Bridge: Decouples an abstraction from its implementation so that the two can vary independently.
• Composite: Composes objects into tree structures to represent hierarchies part-whole.
• Decorator: Dynamically adds responsibilities to an object by wrapping it.
• Facade: Provides a unified interface to a set of interfaces in a subsystem.
• Flyweight: Uses sharing to support large numbers of fine-grained objects efficiently.
• Proxy: Provides a surrogate or placeholder for another object to control access to it.

Behavioral:

• Chain of Responsibility: Passes requests along a chain of potential handlers.
• Command: Encapsulates a request as an object, allowing parameterization of clients with different requests, queuing of requests, or operations like undo.
• Interpreter: Defines a grammatical representation for a language and an interpreter to evaluate sentences in that language.
• Iterator: Provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation.
• Mediator: Defines an object that encapsulates how a set of objects interact.
• Memento: Saves and restores an object's previous state without exposing its implementation details.
• Observer: Defines a one-to-many dependency so that when one object changes state, all its dependents are notified and updated automatically.
• State: Allows an object to alter its behavior when its internal state changes.
• Strategy: Defines a family of algorithms, encapsulates each one, and makes them interchangeable.
• Template Method: Defines the skeleton of an algorithm in an operation, deferring some steps to subclasses.
• Visitor: Represents an operation to be performed on elements of an object structure. It lets you define a new operation without changing the classes of the elements.

Additionally, I am familiar with more specific patterns used in particular development areas, such as MVC, MVP, MVVM (for presentation), as well as integration patterns like Publisher/Subscriber.