IBM Backend Java Developer Interview Questions and Answers

REST API is used to communicate between client and server using HTTP methods like GET, POST, PUT, DELETE.

• REST API allows clients to access and manipulate resources on a server using standard HTTP methods.

• It uses URLs to identify resources and HTTP methods to perform actions on those resources.

• Common HTTP methods used in REST API are GET (retrieve data), POST (create data), PUT (update data), DELETE (remove data).

• REST A...read more

Annotations in Spring Boot are used to provide metadata about the application and its components.

• Annotations are used to configure Spring Boot applications, define beans, handle requests, etc.

• Examples include @SpringBootApplication, @RestController, @Autowired, @RequestMapping, etc.

Java 8 introduced several new features including lambda expressions, functional interfaces, streams, and default methods in interfaces.

• Lambda expressions allow for more concise code and enable functional programming.

• Functional interfaces are interfaces with a single abstract method, used for lambda expressions.

• Streams provide a way to work with collections of objects in a functional style.

• Default methods in interfaces ...read more

Interfaces in Java are implemented using the 'implements' keyword, allowing classes to provide specific implementations for methods defined in the interface.

• Interfaces in Java define a contract for classes to implement, specifying method signatures without implementations.

• A class can implement multiple interfaces by separating them with commas.

• Classes implementing an interface must provide concrete implementations for ...read more

Stream API in Java provides a way to process collections of objects in a functional style.

• Stream API allows for functional-style operations on collections like map, filter, reduce, etc.

• It supports lazy evaluation, meaning operations are only performed when needed.

• Streams can be sequential or parallel, depending on the source and operations used.

Spring Boot simplifies the setup and development of Spring applications by providing a convention-over-configuration approach.

• Spring Boot eliminates the need for XML configuration by using annotations and sensible defaults.

• It includes embedded servers like Tomcat, Jetty, or Undertow, making it easy to deploy standalone applications.

• Auto-configuration feature reduces the amount of boilerplate code needed to set up a Spr...read more

throw is a keyword used to explicitly throw an exception, while Throwable is a class that serves as the base class for all exceptions in Java.

• throw is used to throw an exception in a method, while Throwable is the superclass of all exceptions in Java.

• throw is followed by an instance of Throwable class or its subclasses, while Throwable is a class that provides common methods for handling exceptions.

• Example: throw new N...read more