Deloitte Digital Fullstack Java Developer Interview Questions and Answers

React is a JavaScript library for building user interfaces. Deployment can be done using various methods.

• React features include virtual DOM, component-based architecture, JSX syntax, and state management.

• Deployment can be done using tools like Heroku, Netlify, AWS, or manually by building and serving static files.

• Continuous integration and deployment (CI/CD) pipelines can be set up to automate the deployment process.

• Se...read more

Dependency Injection is a design pattern in which components are given their dependencies rather than creating them internally.

• In Dependency Injection, the dependencies of a class are injected from the outside, typically through constructor injection or setter injection.

• This helps in achieving loose coupling between classes, making the code more modular and easier to test.

• Example: Spring Framework uses Dependency Injec...read more

Exceptions in inheritance are handled using try-catch blocks in the subclass.

• Inherited methods can throw exceptions that need to be caught in the subclass.

• Subclass can override superclass methods and handle exceptions differently.

• Superclass methods can declare checked exceptions that subclasses must handle.

• Exceptions can be rethrown or wrapped in a new exception in the subclass.

Immutable class is a class whose instances cannot be modified after creation.

• Immutable classes have all fields as final and private.

• Immutable classes do not have any setter methods.

• Examples of immutable classes in Java are String, Integer, and LocalDate.

I have implemented design patterns like Singleton, Factory, and Observer in various projects.

• Implemented Singleton pattern to ensure only one instance of a class exists.

• Utilized Factory pattern to create objects without specifying the exact class of object that will be created.

• Used Observer pattern to establish a one-to-many dependency between objects, so that when one object changes state, all its dependents are notif

To improve the performance of a running application, consider optimizing code, database queries, caching, and server resources.

• Optimize code by identifying and fixing bottlenecks, reducing unnecessary loops, and improving algorithms.

• Optimize database queries by using indexes, avoiding unnecessary joins, and limiting the amount of data retrieved.

• Implement caching mechanisms to store frequently accessed data in memory, r...read more