Deqode Java Developer Interview Questions and Answers

Annotations like @Qualifier and @Transactional are used in Spring Boot for dependency injection and transaction management.

• Annotations like @Qualifier are used to specify which bean to inject when multiple beans of the same type are present.

• Annotations like @Transactional are used to mark a method as transactional, allowing for rollback in case of exceptions.

• Annotations like @Component, @Service, @Repository are used for component scanning and auto-wiring.

• Annotations like @Re...read more

OOP is a programming paradigm based on the concept of objects, which can contain data in the form of fields and code in the form of procedures.

• OOP focuses on creating objects that interact with each other to solve problems.

• Key concepts include encapsulation, inheritance, and polymorphism.

• Encapsulation involves bundling data and methods that operate on the data into a single unit.

• Inheritance allows classes to inherit attributes and methods from other classes.

• Polymorphism enabl...read more

Microservices are a software architectural style that structures an application as a collection of loosely coupled services.

• Each service is self-contained and can be developed, deployed, and scaled independently.

• Communication between services typically occurs over lightweight protocols like HTTP or messaging queues.

• Microservices allow for greater flexibility, scalability, and resilience compared to monolithic architectures.

• Examples of microservices patterns include API Gatewa...read more

Spring Boot is a framework for building Java-based applications with minimal configuration.

• Spring Boot simplifies the process of creating stand-alone, production-grade Spring-based applications.

• It provides a range of features including embedded servers, auto-configuration, and production-ready metrics.

• Spring Boot allows developers to quickly set up and run applications with ease, reducing the need for manual configuration.

• It is widely used in enterprise applications for its e...read more

Asynchronous APIs in Java can be created using @Qualifier annotation to specify which bean to inject when multiple beans of the same type are present.

• Use @Qualifier annotation along with @Autowired to specify the bean to be injected.

• For example, if there are multiple beans of the same type, use @Qualifier("beanName") to specify which bean to inject.

• This helps in resolving ambiguity when multiple beans of the same type are present in the application context.

Communication between microservices is typically done through APIs or messaging systems.

• Microservices communicate with each other using APIs, such as REST or gRPC.

• Message brokers like Kafka or RabbitMQ are commonly used for asynchronous communication between microservices.

• Service mesh tools like Istio can help manage communication between microservices by handling service discovery, load balancing, and security.

• Event-driven architecture can be used for communication between m...read more