Angular interview questions tailored for a Java FullStack Developer ( AI Generated)

 Here’s a list of Angular interview questions tailored for a Java Fullstack Developer, along with concise answers:

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Basic Questions

1. What is Angular?

• Answer:
  Angular is a TypeScript-based open-source framework developed by Google for building dynamic, single-page web applications (SPAs). It provides tools for data binding, dependency injection, routing, and more.

2. Explain the architecture of Angular.

• Answer:
  Angular follows a component-based architecture. Key building blocks include:
  • Components: Define the UI and logic for a part of the application.
  • Modules: Group related components, directives, pipes, and services.
  • Templates: HTML with Angular directives and bindings.
  • Services: For reusable business logic and data communication.
  • Dependency Injection: Manages service instances efficiently.
  • Routing: Handles navigation and views.

3. What are components, and how are they different from directives?

• Answer:
  • Components: Building blocks for UI, defined using @Component decorator. They manage a specific view.
  • Directives: Used to manipulate DOM elements, behaviors, or templates, defined using @Directive decorator.

4. Explain data binding in Angular.

• Answer:
  Angular supports four types of data binding:
  • Interpolation: {{expression}} for binding data to templates.
  • Property Binding: [property]="expression".
  • Event Binding: (event)="handler()".
  • Two-Way Binding: [(ngModel)]="property" for syncing data between the view and model.

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Intermediate Questions

5. What is Angular CLI, and why is it used?

• Answer:
  Angular CLI (Command Line Interface) is a tool to initialize, develop, scaffold, and maintain Angular applications. It simplifies project setup and maintenance by automating repetitive tasks.

6. How does dependency injection work in Angular?

• Answer:
  Dependency Injection (DI) is a design pattern in Angular where services or objects are injected into components, directives, or other services. Angular’s DI system uses providers defined in modules or components to create and inject instances as needed.

7. What are lifecycle hooks in Angular?

• Answer:
  Lifecycle hooks are methods that allow you to tap into different phases of a component or directive's lifecycle. Common hooks include:
  • ngOnInit: Called after component initialization.
  • ngOnChanges: Responds to changes in input properties.
  • ngOnDestroy: Cleanup logic before component destruction.

8. What is lazy loading in Angular?

• Answer:
  Lazy loading is a technique to load feature modules on demand rather than at application startup. This improves performance and reduces initial load time. It’s implemented using the loadChildren property in routing configuration.

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Advanced Questions

9. How do you handle state management in Angular applications?

• Answer:
  State management can be handled using libraries like NgRx or Akita. These libraries implement reactive programming and manage application state as a single source of truth.

10. How does Angular handle forms?

• Answer:
  Angular provides two approaches for handling forms:
  • Template-Driven Forms: Easier for simple forms; uses directives like ngModel.
  • Reactive Forms: For complex forms; uses a programmatic approach with FormGroup and FormControl.

11. Explain Angular's change detection mechanism.

• Answer:
  Angular uses a unidirectional data flow and a tree structure to detect and update changes. When a change occurs, Angular triggers change detection from the root component and propagates it down the component tree.

12. What are pipes in Angular?

• Answer:
  Pipes are used to transform data in templates. Angular provides built-in pipes like DatePipe, CurrencyPipe, and UpperCasePipe. Custom pipes can also be created using @Pipe decorator.

13. What is the difference between Promise and Observable in Angular?

• Answer:
  • Promise: Handles a single asynchronous operation, is eager, and non-cancellable.
  • Observable: Handles streams of asynchronous data, is lazy, and cancellable. Used in Angular's HttpClient for HTTP calls.

14. How does routing work in Angular?

• Answer:
  Routing in Angular allows navigation between different views. It uses the RouterModule to define routes in the AppRoutingModule. Key features include parameterized routes, guards, and lazy loading.

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Scenario-Based Questions

15. How would you integrate Angular with a Java Spring Boot backend?

• Answer:
  • Expose REST APIs in Spring Boot using @RestController.
  • Use Angular's HttpClient to make HTTP requests to these APIs.
  • Configure CORS in Spring Boot for cross-origin requests.
  • Implement security (e.g., JWT) for authentication and authorization.

16. How would you optimize the performance of an Angular application?

• Answer:
  • Use Ahead-of-Time (AOT) compilation.
  • Implement lazy loading for feature modules.
  • Use OnPush change detection strategy.
  • Minimize bundle size with tree-shaking and optimization tools.
  • Use caching for HTTP requests and assets.

17. How do you secure Angular applications?

• Answer:
  • Use JWT for authentication.
  • Sanitize user inputs to prevent XSS.
  • Secure routes using Route Guards.
  • Use HTTPS and content security policies.

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Practical Exercise

18. Write a simple Angular service to fetch user data from a backend API.

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root',
})
export class UserService {
  private apiUrl = 'https://api.example.com/users';

  constructor(private http: HttpClient) {}

  getUsers(): Observable<any> {
    return this.http.get(this.apiUrl);
  }
}

19. Explain how to implement a custom directive in Angular.

• Answer:
  Create a directive using the @Directive decorator. Example:

import { Directive, ElementRef, Renderer2, HostListener } from '@angular/core';

@Directive({
  selector: '[appHighlight]',
})
export class HighlightDirective {
  constructor(private el: ElementRef, private renderer: Renderer2) {}

  @HostListener('mouseenter') onMouseEnter() {
    this.renderer.setStyle(this.el.nativeElement, 'backgroundColor', 'yellow');
  }

  @HostListener('mouseleave') onMouseLeave() {
    this.renderer.removeStyle(this.el.nativeElement, 'backgroundColor');
  }
}

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This set of questions covers essential Angular concepts, integration with Java backend, and practical scenarios relevant to a fullstack developer role.

( Generated by ChatGpt)