How can you create Singleton class in Java?
- By declaring a private constructor and a public static method that returns the only instance of the class
- By declaring all of its variables and methods as final
- By declaring all of its variables and methods as static
- By implementing the Cloneable interface
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.
What is the purpose of the MVC pattern?
- The Model-View-Controller (MVC) pattern is used to create a modular and scalable code structure. The Model represents the data, the View displays the data, and the Controller handles user interactions and updates the Model.
- The Model-View-Controller (MVC) pattern is used to create a simple, flexible and reusable code structure. The Model represents the data, the View displays the data, and the Controller handles user interactions and updates the Model.
- The Model-View-Controller (MVC) pattern is used to provide a common interface for accessing application data. The Model represents the data, the View displays the data, and the Controller manages the flow of data between the Model and the View.
- The Model-View-Controller (MVC) pattern is used to separate application logic from presentation logic and data management. The Model represents the data, the View displays the data, and the Controller manages the flow of data between the Model and the View.
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.
What is the Deadly Diamond of Death?
- The Deadly Diamond of Death is a situation in which a class has too many responsibilities and becomes overly complex.
- The Deadly Diamond of Death is a situation in which a class inherits from two classes with conflicting attributes.
- The Deadly Diamond of Death is a situation in which a class inherits from two classes with conflicting implementations of a method.
- The Deadly Diamond of Death is a situation in which multiple inheritance results in ambiguity and complexity in the inheritance hierarchy of a system.
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.
What is the difference between the Bridge and Filter patterns?
- The Bridge pattern allows for loose coupling between the sender of a request and its receivers, while the Filter pattern provides a unified interface to a set of interfaces in a subsystem.
- The Bridge pattern decouples an abstraction from its implementation, allowing the two to vary independently. The Filter pattern provides a way to filter requests that pass through a set of handlers.
- The Bridge pattern is used to create objects based on a blueprint, while the Filter pattern provides a way to convert the interface of a class into another interface clients expect.
- The Bridge pattern is used to filter requests that pass through a set of handlers, while the Filter pattern decouples an abstraction from its implementation.
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.
What is Prototype pattern?
- A design pattern that creates objects by cloning existing objects, rather than creating new instances from scratch
- A design pattern that creates objects in a step-by-step manner, allowing for more control over the object creation process
- A design pattern that helps to reduce the number of objects in the system, making it more efficient
- A design pattern that promotes the loose coupling between objects, making the system easier to maintain and extend
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.
What is the difference between the Adapter and Bridge patterns?
- None of the above
- The Adapter and Bridge patterns are the same
- The Adapter pattern converts the interface of one class into another, while the Bridge pattern decouples an abstraction from its implementation, allowing the two to be varied independently
- The Adapter pattern decouples an abstraction from its implementation, while the Bridge pattern converts the interface of one class into another
The Adapter pattern converts the interface of one class into another, while the Bridge pattern decouples an abstraction from its implementation, allowing the two to be varied independently
What is the difference between the Template patterns and the Strategy pattern?
- Template patterns allow for the implementation of a specific algorithm to be swapped out at runtime, while Strategy patterns provide a set of steps to be followed in a defined order. Template patterns are meant to be composed, while Strategy patterns are meant to be subclassed.
- Template patterns and Strategy patterns are the same thing.
- Template patterns and Strategy patterns have no relationship to each other.
- Template patterns provide a set of steps to be followed in a defined order, while Strategy patterns allow for the implementation of a specific algorithm to be swapped out at runtime. Template patterns are meant to be subclassed, while Strategy patterns are meant to be composed.
The Template pattern provides a set of steps to be followed in a defined order, while the Strategy pattern allows for the implementation of a specific algorithm to be swapped out at runtime. Template patterns are meant to be subclassed, while Strategy patterns are meant to be composed.
What is Front Controller pattern?
- A design pattern to handle communication between objects
- A design pattern to handle database connections
- A design pattern to manage the flow of control from a centralized handler
- A design pattern to provide a unified interface to a set of interfaces
The Front Controller pattern provides a centralized handler for requests coming from the client. It coordinates the work of different request handlers to provide a unified interface for the user.
What are J2EE Patterns?
- A set of design patterns for software development using the C++ programming language
- A set of design patterns for software development using the Java programming language
- A set of design patterns for software development using the Python programming language
- A set of design patterns for software development using the Ruby programming language
J2EE Patterns are a set of design patterns that are specifically tailored to the Java 2 Platform, Enterprise Edition (J2EE) technology. These patterns provide a solution to common problems that arise in J2EE-based software development, such as implementing security, managing transactions, and integrating with other systems.
How does the Observer pattern differ from the Pub-Sub pattern?
- The Observer pattern involves a one-to-many relationship between objects, where one object (the subject) maintains a list of its dependents (observers) and notifies them of any changes, while the Pub-Sub pattern involves the publish and subscribe mechanism, where the publisher does not know the subscribers and the subscribers do not know the publishers.
- The Observer pattern involves the publish and subscribe mechanism, where the publisher does not know the subscribers and the subscribers do not know the publishers, while the Pub-Sub pattern involves a one-to-many relationship between objects, where one object (the subject) maintains a list of its dependents (observers) and notifies them of any changes.
- The Observer pattern is a type of the Pub-Sub pattern.
- The Pub-Sub pattern is a type of the Observer pattern.
The Observer pattern involves a one-to-many relationship between objects, where one object (the subject) maintains a list of its dependents (observers) and notifies them of any changes, while the Pub-Sub pattern involves the publish and subscribe mechanism, where the publisher does not know the subscribers and the subscribers do not know the publishers.