Deqode Java Developer Interview Questions and Answers

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 at...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 configurat...read more

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-d...read more

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 f...read more

Rotate an array in groups of three elements in reverse order.

• Split the array into chunks of 3: {1,2,3}, {4,5,6}, {7,8,9}.

• Reverse each chunk: {3,2,1}, {6,5,4}, {9,8,7}.

• Concatenate the reversed chunks to get the final array: {3,2,1,6,5,4,9,8,7}.

• Example: For input {1,2,3,4,5,6,7,8,9}, output is {3,2,1,6,5,4,9,8,7}.

HTTP methods are used to indicate the desired action to be performed on a resource.

• GET - Retrieve data from a server

• POST - Submit data to be processed by a server

• PUT - Update a resource on the server

• DELETE - Remove a resource from the server

• PATCH - Partially update a resource on the server