Today, we show you top 50 Java Design Patterns Interview Questions. Design pattern represents the best practices evolved over a period of time by experienced software developers. A design pattern systematically names, motivates, and explains a general design that addresses a recurring design problem in object-oriented systems.
1.When will you use Strategy Design Pattern in Java?
2.What is Observer design pattern?
3.What are the examples of Observer design pattern in JDK?
4.How Strategy design pattern is different from State design pattern in Java?
5.Can you explain Decorator design pattern with an example in Java?
6.What is a good scenario for using Composite design Pattern in Java?
7.Have you used Singleton design pattern in your Java project?
8.What are the main uses of Singleton design pattern in Java project?
9.Why java.lang.Runtime is a Singleton in Java?
10.What is the way to implement a thread-safe Singleton design pattern in Java?
11.What are the examples of Singleton design pattern in JDK?
12.What is Template Method design pattern in Java?
13.What are the examples of Template method design pattern in JDK?
14.Can you tell some examples of Factory Method design pattern implementation in Java?
15.What is the benefit we get by using static factory method to create object?
16.What are the examples of Builder design pattern in JDK?
17.What are the examples of Abstract Factory design pattern in JDK?
18.What are the examples of Decorator design pattern in JDK?
19.What are the examples of Proxy design pattern in JDK?
20.What are the examples of Chain of Responsibility design pattern in JDK?
21.What are the main uses of Command design pattern?
22.What are the examples of Command design pattern in JDK?
23.What are the examples of Interpreter design pattern in JDK?105.What are the examples of Mediator design pattern in JDK?
24.What are the examples of Strategy design pattern in JDK?
25.What are the examples of Visitor design pattern in JDK?
26.How Decorator design pattern is different from Proxy pattern?
27.What are the different scenarios to use Setter and Constructor based injection in Dependency Injection (DI) design pattern?
28.What are the different scenarios for using Proxy design pattern?
29.What is the main difference between Adapter and Proxy design pattern?
30.When will you use Adapter design pattern in Java?
31.What are the examples of Adapter design pattern in JDK?
32.What is the difference between Factory and Abstract Factory design pattern?
33.What is Open/closed design principle in Software engineering?
34.What is SOLID design principle?
35.What is Builder design pattern?
36.What are the different categories of Design Patterns used in Object Oriented Design?
37.What is the design pattern suitable to access elements of a Collection?
38.How can we implement Producer Consumer design pattern in Java?
39.What design pattern is suitable to add new features to an existing object?
40.Which design pattern can be used when to decouple abstraction from the implementation?
41.Which is the design pattern used in Android applications?
42.How can we prevent users from creating more than one instance of singleton object by using clone() method?
43.What is the use of Interceptor design pattern?
44.What are the Architectural patterns that you have used?
45.What are the popular uses of Façade design pattern?
46.What is the difference between Builder design pattern and Factory design pattern?
47.What is Memento design pattern?
48.What is an AntiPattern?
49. What is a Data Access Object (DAO) design pattern?
That’s all about Top 50 Java Design Patterns Interview Questions.