Deloitte Java Developer Interview Questions and Answers

Threads in Java allow multiple tasks to run concurrently within a single program.

• Threads are lightweight sub-processes that share the same memory space.

• They are used to improve performance by allowing tasks to run simultaneously.

• Examples include creating a new thread using the Thread class or implementing the Runnable interface.

Familiarity with key Spring modules enhances Java development, enabling robust, scalable applications with ease.

• Spring Core: Provides the foundational features of the Spring Framework, including Dependency Injection (DI). Example: @Autowired annotation.

• Spring MVC: A web framework for building web applications. Example: Using @Controller and @RequestMapping for handling requests.

• Spring Boot: Simplifies the setup and dev...read more

OOPs concept in Java includes keywords and access specifiers for defining classes and objects.

• OOPs concept focuses on objects and classes for code organization

• Keywords like 'class', 'extends', 'implements' are used for defining classes and inheritance

• Access specifiers like 'public', 'private', 'protected' control visibility of class members

Set is a collection of unique elements with no specific order, while list is a collection of elements with a specific order and allows duplicates.

• Set does not allow duplicate elements, while list allows duplicates.

• Set does not maintain insertion order, while list maintains insertion order.

• Examples: HashSet is a set implementation, ArrayList is a list implementation.

To create a REST API, you need to define endpoints, implement CRUD operations, handle HTTP methods, and use frameworks like Spring Boot.

• Define endpoints for different resources (e.g. /users, /products)

• Implement CRUD operations (Create, Read, Update, Delete) for each endpoint

• Handle HTTP methods like GET, POST, PUT, DELETE

• Use frameworks like Spring Boot to simplify API development

Lambda functions in Java 8 allow for concise and functional programming style.

• Use the lambda operator '->' to define the lambda function.

• Specify the parameters and the body of the lambda function.

• Example: (int a, int b) -> a + b

I want to join Deloitte because of its reputation for innovation, diverse projects, and opportunities for growth.

• Deloitte is known for its innovative projects and cutting-edge technology, which aligns with my passion for staying up-to-date with the latest trends in Java development.

• I am impressed by Deloitte's diverse range of projects and clients, which will provide me with valuable experience and the opportunity to w...read more

Solid design principles are a set of best practices for designing software that is maintainable, scalable, and flexible.

• Single Responsibility Principle - each class should have only one responsibility

• Open/Closed Principle - classes should be open for extension but closed for modification

• Liskov Substitution Principle - objects of a superclass should be replaceable with objects of its subclasses without affecting the pro...read more

Design patterns in Java are reusable solutions to common problems in software design.

• Design patterns help in creating flexible, maintainable, and scalable code.

• Examples of design patterns in Java include Singleton, Factory, Observer, and Strategy.

• Each design pattern has its own purpose and can be applied in different scenarios.

• Understanding design patterns is essential for Java developers to write efficient code.