Which of the following is a potential drawback of the Singleton pattern?
It simplifies dependency injection.
It promotes code reusability.
It makes unit testing more challenging.
It reduces the need for global variables.
How does the Command Pattern achieve decoupling?
By relying on a central registry to map requests to their handlers.
By directly connecting the object making the request with the object fulfilling it.
By introducing an intermediary object (the Command) between the invoker and the receiver.
By using inheritance to create specialized request handlers.
When is it appropriate to consider using the Facade Pattern?
When the interaction with a subsystem is already simple and straightforward.
When dealing with a small, well-defined set of classes.
When you want to expose the internal implementation details of a system.
When you need to simplify the interface to a complex subsystem.
How does the Decorator Pattern achieve the dynamic addition of responsibilities?
By using reflection to alter the behavior of methods during execution.
By using inheritance to create subclasses with extended functionality.
By modifying the source code of the decorated object at runtime.
By composing objects, where decorators wrap the component and delegate to it.
What potential issue could arise if an observer modifies the subject's state during notification?
It could lead to an infinite loop.
All of the above
It could result in unexpected behavior and make the system harder to reason about.
It violates the principle of least astonishment.
Which of these is a common use case for the Observer pattern?
Creating a singleton object.
Implementing a notification system.
Implementing an undo/redo mechanism.
Defining a factory for creating objects.
Which of these is NOT a benefit of using the Facade Pattern?
Increased code complexity and difficulty in understanding.
Reduced coupling between client code and the subsystem.
Improved code readability and maintainability.
Shielded clients from the complexities of the subsystem.
In a Facade Pattern implementation, what is the role of the Facade class?
It directly implements the complex logic of the subsystem.
It defines the interfaces for all classes within the subsystem.
It delegates requests to appropriate subsystem classes and returns results.
It restricts access to the subsystem, preventing any external interaction.
In Java, what keyword is commonly used to ensure thread-safe Singleton instantiation?
abstract
volatile
synchronized
final
What is a potential downside of overusing design patterns?
Improved code performance
Increased code readability
Unnecessary complexity and abstraction
Reduced code complexity