Infosys Java Developer Interview Questions, Process, and Tips

Spring Security is a powerful framework for securing Java applications, providing authentication and authorization features.

• Provides comprehensive security services for Java applications.

• Supports authentication via various methods like form-based, basic, and OAuth.

• Allows fine-grained access control using annotations like @PreAuthorize.

• Integrates seamlessly with Spring applications, leveraging the Spring ecosystem.

• Offer...read more

JWT (JSON Web Token) is a compact, URL-safe means of representing claims to be transferred between two parties.

• JWT consists of three parts: Header, Payload, and Signature.

• Header typically contains the type of token (JWT) and the signing algorithm (e.g., HMAC SHA256).

• Payload contains the claims, which can be user data or metadata (e.g., user ID, expiration time).

• Signature is created by combining the encoded header, payl...read more

Filters and Segmentation in Spring Security manage request processing and user access control.

• Filters are components that intercept requests and responses in the Spring Security filter chain.

• Examples of filters include UsernamePasswordAuthenticationFilter and BasicAuthenticationFilter.

• Segmentation refers to dividing users into roles or groups for access control.

• Using @PreAuthorize or @Secured annotations allows method-

Microservices use JWT for secure authentication, enabling them to verify each other's identity without centralized control.

• Microservices issue a JWT after user authentication, containing claims about the user.

• The JWT is signed with a secret key, ensuring its integrity and authenticity.

• When one microservice needs to call another, it includes the JWT in the request header.

• The receiving microservice verifies the JWT using...read more

A Functional Interface is an interface with a single abstract method, enabling lambda expressions in Java.

• Functional interfaces are used primarily with lambda expressions.

• They can have multiple default or static methods but only one abstract method.

• Common examples include Runnable, Callable, and Comparator.

• You can create your own functional interfaces using the @FunctionalInterface annotation.

Implementing Runnable using lambda expressions simplifies thread creation in Java.

• Lambda expressions provide a clear and concise way to represent a functional interface.

• Runnable is a functional interface with a single abstract method: run().

• Example of Runnable using lambda: Runnable task = () -> System.out.println('Running in a thread');

• To start a thread: new Thread(task).start();

Spring Boot's default server is Tomcat, but you can easily switch to others like Jetty or Undertow.

• Spring Boot uses Tomcat as the default embedded server.

• To use Jetty, add the dependency: 'spring-boot-starter-jetty' in your pom.xml.

• For Undertow, include 'spring-boot-starter-undertow' in your dependencies.

• You can exclude Tomcat by adding 'exclude = {Tomcat.class}' in your @SpringBootApplication annotation.

Profiles in Java are configurations that define specific settings for different environments.

• Profiles allow you to customize application behavior based on the environment (e.g., development, testing, production).

• You can define profiles in the application.properties or application.yml file using 'spring.profiles.active'.

• Example: 'spring.profiles.active=dev' activates the 'dev' profile, loading specific configurations.

• Pr...read more

The @Primary annotation in Spring indicates a preferred bean when multiple candidates are available for autowiring.

• @Primary is used in Spring Framework for dependency injection.

• It helps resolve ambiguity when multiple beans of the same type exist.

• Example: If you have two beans of type 'DataSource', marking one with @Primary will make it the default choice.

• It can be combined with @Qualifier for more specific bean select

Spring Boot's default port is 8080, and it can be changed via application properties or command line arguments.

• Default port: 8080.

• Change via application.properties: server.port=9090.

• Change via command line: java -jar app.jar --server.port=9090.

• Change via YAML: server: port: 9090

The Optional class is a container that may or may not hold a non-null value, helping to avoid NullPointerExceptions.

• Introduced in Java 8 to represent optional values.

• Helps in avoiding null checks and NullPointerExceptions.

• Methods include isPresent(), ifPresent(), orElse(), and orElseGet().

• Example: Optional<String> name = Optional.ofNullable(getName());

• Example: name.ifPresent(n -> System.out.println(n));

RestTemplate is a synchronous client to perform HTTP requests in Spring applications.

• Simplifies interaction with RESTful web services.

• Supports various HTTP methods: GET, POST, PUT, DELETE.

• Example: RestTemplate.getForObject(url, responseType) retrieves data.

• Can handle JSON/XML responses automatically.

• Easily configurable with message converters for different content types.

Receiving negative feedback is an opportunity for growth; I approach it with an open mind and a willingness to improve.

• Listen actively to the feedback without interrupting, showing respect for the manager's perspective.

• Ask clarifying questions to fully understand the feedback and the areas needing improvement.

• Reflect on the feedback and identify specific actions I can take to address the concerns raised.

• Create a plan t...read more

Upon discovering a bug near project completion, I would assess its impact, communicate with stakeholders, and prioritize a fix.

• Assess the severity of the bug: Determine if it's a critical issue that affects functionality or a minor cosmetic issue.

• Communicate with the team: Inform relevant stakeholders, including project managers and team members, about the bug.

• Prioritize the fix: If the bug is critical, prioritize it f...read more

My short-term goal is to enhance my Java skills, while my long-term goal is to lead projects and mentor junior developers.

• Short-term: Master advanced Java frameworks like Spring and Hibernate to improve my development efficiency.

• Short-term: Contribute to open-source projects to gain real-world experience and collaborate with other developers.

• Long-term: Aim for a leadership role where I can guide teams in best practices...read more

Current company may have different priorities, budget constraints, existing systems, or may not see the immediate need for the technology.

• Different priorities: Company may be focusing on other projects or technologies that are deemed more important at the moment.

• Budget constraints: Implementing new technology can be costly and the company may not have the budget for it.

• Existing systems: Company may already have systems...read more

The company has chosen not to utilize XYZ technology due to budget constraints and compatibility issues.

• Budget constraints may have limited the company's ability to invest in new technologies.

• Compatibility issues with existing systems may have prevented the adoption of XYZ technology.

• The company may have determined that the benefits of XYZ technology do not outweigh the costs of implementation.

• There may be alternative ...read more