Ans: I have over 5 years of experience in full-stack development, with a strong focus on Java for back-end development and Angular for front-end development. I've worked on various projects ranging from e-commerce websites to enterprise-level applications, where I was responsible for designing and implementing scalable, maintainable, and efficient systems.

Ans: One notable project was an e-commerce website for a manufacturing company. The front end was built with Angular, providing a dynamic and responsive user interface. In contrast, the back end was developed using Java Spring Boot, handling all business logic and database interactions.

 Ans: I regularly follow official documentation, blogs, and forums. I also participate in online courses and attend webinars and conferences. Additionally, I contribute to open-source projects and engage with the developer community on platforms like GitHub and Stack Overflow.

 Ans: I start by reading official documentation and tutorials, followed by hands-on practice through small projects or coding exercises. When our team decided to adopt Docker for containerization, I quickly learned it by following online courses and setting up a local environment for our application. This allowed us to streamline our development and deployment processes.

 Ans: In a recent project, I worked closely with a UX designer to improve the user interface of our application. My role was to implement the designs and ensure they were responsive and user-friendly. I provided feedback on feasibility and suggested improvements based on technical constraints. Our collaboration resulted in a more intuitive and visually appealing application.

 Ans: I prioritize tasks based on deadlines, project impact, and dependencies. I use project management tools like Jira to keep track of tasks and their priorities. Regularly reviewing my task list and communicating with stakeholders helps ensure that I focus on the most critical tasks first.

 Ans: In one project, we encountered unexpected performance issues close to the release date. I led a team to identify the bottlenecks, optimise the code, and re-prioritise features to ensure a stable release. This experience taught me the importance of early performance testing and having contingency plans.

 Ans: The introduction of lambda expressions and the Stream API are particularly useful as they enable more functional programming styles and more concise, readable code. Additionally, the `Optional` class helps in handling null values more gracefully, reducing the risk of `NullPointerException`.

 Ans: Abstract classes can have both abstract and concrete methods and can maintain state through fields. Interfaces, on the other hand, cannot have instance fields and were traditionally used only to declare abstract methods (though they can now have default and static methods). Multiple inheritance is possible with interfaces, while a class can extend only one abstract class.

 Ans: I use Maven or Gradle to manage project dependencies. These tools allow me to define dependencies in a `pom.xml` or `build.gradle` file, which they then handle automatically, ensuring all required libraries are available and up-to-date.

 Ans: The Spring Framework is a comprehensive framework for enterprise Java development. It simplifies the development of Java applications by providing infrastructure support for various features like dependency injection, transaction management, and web applications. Spring Boot, a part of the Spring ecosystem, further simplifies application setup and development by providing pre-configured templates and settings.

 Ans: I use try-catch blocks to handle exceptions and ensure proper resource management with try-with-resources. For example:

Additionally, I use custom exceptions and appropriate logging to provide more context about errors.

 Ans: RESTful services are web services that adhere to REST architecture principles, utilizing HTTP methods (GET, POST, PUT, DELETE) for CRUD operations. In Java, I've implemented RESTful services using Spring Boot by creating REST controllers annotated with `@RestController`, mapping HTTP requests to handler methods using `@RequestMapping`, `@GetMapping`, etc.

 Ans: JPA (Java Persistence API) is a specification for object-relational mapping in Java. Hibernate is an implementation of the JPA specification, providing the tools to map Java objects to database tables and perform CRUD operations. I use Hibernate for its robust features and ease of integration with Spring.

 Ans: I've designed and implemented microservices using Spring Boot and Spring Cloud. Each service is independently deployable, focused on a specific business capability, and communicates with other services via RESTful APIs or messaging queues like RabbitMQ. I've also used tools like Eureka for service discovery and Zuul for API gateway management.

Q:16. How to perform testing in Java? What tools and frameworks are used? 

 Ans: JUnit is used for unit testing, Mockito for mocking dependencies, and Spring's testing support for integration tests. For end-to-end testing, one can use Selenium. Continuous integration tools like Jenkins ensure that tests are run automatically as part of the build process.

 Ans: Angular (versions 2 and above) is a complete rewrite of AngularJS (version 1.x). Angular uses TypeScript, a statically typed language, while AngularJS uses JavaScript. Angular's architecture is component-based, whereas AngularJS uses controllers and $scope for binding. Angular also offers better performance and more powerful templating and dependency injection compared to AngularJS.

 Ans: By the use of services we can manage states across components, and for more complex state management, we should leverage libraries like NgRx, which implements Redux patterns. This allows for a single source of truth, making the state predictable and easier to debug.

 Ans: Angular Modules (`@NgModule`) help organize an application into cohesive blocks of functionality. They allow for lazy loading, and encapsulation of components, directives, and services, and they make the application scalable and maintainable by separating features into different modules.

 Ans: Angular lifecycle hooks like `ngOnInit`, `ngOnChanges`, `ngOnDestroy`, and others allow developers to hook into key moments in a component's lifecycle. For example, I use `ngOnInit` to fetch data from a service when a component is initialized and `ngOnDestroy` to clean up subscriptions to prevent memory leaks.

 Ans: Reactive Forms provide a model-driven approach to handling form inputs, allowing for more complex form logic and validation, while Template-Driven Forms rely on Angular directives in the template. One should prefer Reactive Forms for their scalability and more explicit control over form behavior.

 Ans: Angular's dependency injection (DI) system allows you to inject dependencies (services, other components) into your classes rather than hardcoding them. This promotes loose coupling, makes components more testable, and simplifies the code by managing object lifecycles and dependencies.

 Ans: One can apply lazy loading to load modules only when needed, implement OnPush change detection to minimize unnecessary checks, use trackBy in ngFor for efficient DOM updates, and leverage Angular's built-in tools like Ahead-of-Time (AOT) compilation and tree shaking to reduce the bundle size.

 Ans: we can use the Angular Router module, defining routes in the `app-routing.module.ts` file, and use `RouterModule.forRoot()` for root configuration and `RouterModule.forChild()` for feature modules. Also, one can implement route guards for authentication and authorization and use lazy loading for large feature modules.

 Ans: In a large-scale application, lazy loading is implemented to improve the initial load time. By defining separate feature modules and using the `loadChildren` property in the route configuration and ensured that only the necessary modules were loaded when a particular route was accessed.

Q:26. How do you ensure seamless communication between the front-end (Angular) and back-end (Java) in your applications? 

 Ans: I use RESTful APIs to facilitate communication between the front-end and back-end. I ensure that the APIs are well-documented using tools like Swagger, handle CORS appropriately, and use consistent data formats (usually JSON). For real-time updates, I use WebSockets or server-sent events.

 Ans: In one project, we faced performance issues due to a large number of database queries. I optimized the database schema, used indexing, and implemented caching on the server side. On the front end, I implemented pagination and infinite scroll to manage data rendering efficiently.

 Ans: I use JWT (JSON Web Tokens) for stateless authentication and Spring Security on the back-end to handle authorization. On the front-end, I store the JWT in local storage or cookies and use route guards to protect routes based on user roles and permissions.

 Ans: I use Git for version control, following a branching strategy like GitFlow. I ensure that all team members commit frequently, write meaningful commit messages, and regularly merge changes to avoid conflicts. Pull requests and code reviews are integral to our workflow to maintain code quality.

 Ans: I perform validation on the client side using Angular's form validation mechanisms to provide immediate feedback to users. On the server side, I use Java Bean Validation (e.g., Hibernate Validator) to ensure data integrity and security. This two-layer validation ensures that data is correctly formatted and adheres to business rules before being processed or stored.