Infosys Springboot Developer Interview Questions and Answers

Spring filters are components in Spring framework that intercept incoming HTTP requests and outgoing HTTP responses.

• Filters are used to perform tasks like logging, authentication, authorization, etc.

• They are configured in the web.xml file or using annotations like @WebFilter.

• Example: javax.servlet.Filter interface is implemented to create custom filters.

Flat map is used to flatten nested collections, while map is used to transform elements in a collection.

• Flat map is used when you have a collection of collections and you want to flatten it into a single collection.

• Map is used to transform each element in a collection using a given function.

• Example: Using flatMap to flatten a list of lists - list.stream().flatMap(List::stream).collect(Collectors.toList())

• Example: Using...read more

Stream API in Java 8 allows for functional-style operations on collections.

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

• It supports operations like filter, map, reduce, and collect.

• Example: List<String> names = Arrays.asList("Alice", "Bob", "Charlie"); Stream<String> stream = names.stream();

• Example: List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5); int sum = numb...read more

Java 8 introduced parallel programming concepts like streams, parallel streams, and CompletableFuture.

• Java 8 introduced streams which allow for functional-style operations on collections.

• Parallel streams allow for parallel processing of stream elements, improving performance on multi-core processors.

• CompletableFuture class enables asynchronous programming by representing a future result of an asynchronous computation.

Abstract classes can have both abstract and non-abstract methods, while interfaces can only have abstract methods.

• Abstract classes can have constructors, fields, and methods, while interfaces cannot.

• A class can implement multiple interfaces but can only extend one abstract class.

• Abstract classes are used to define a common behavior for subclasses, while interfaces are used to define a contract for classes to implement.

• ...read more

SOLID is a set of five design principles to make software designs more understandable, flexible, and maintainable.

• S - Single Responsibility Principle: A class should have only one reason to change.

• O - Open/Closed Principle: Software entities should be open for extension but closed for modification.

• L - Liskov Substitution Principle: Objects of a superclass should be replaceable with objects of its subclasses without aff...read more

Static keyword is used in Java to create class-level variables and methods.

• Static variables are shared among all instances of a class

• Static methods can be called without creating an instance of the class

• Static keyword can also be used to create static blocks for initialization

Method overloading is having multiple methods in the same class with the same name but different parameters. Method overriding is having a method in a subclass with the same name and parameters as a method in its superclass.

• Method overloading allows a class to have multiple methods with the same name but different parameters.

• Method overriding occurs when a subclass provides a specific implementation of a method that is...read more

RestController is specialized version of controller used for RESTful web services in Spring framework.

• RestController is used to create RESTful web services that return JSON or XML data, while Controller is used to create web pages that return HTML data.

• RestController annotation is a combination of @Controller and @ResponseBody annotations.

• RestController is typically used for building RESTful APIs, while Controller is u...read more

The @Bean annotation is used to define a method that returns an object to be registered as a bean in the Spring application context. The @Component annotation is used to indicate that a class is a Spring component.

• The @Bean annotation is used on methods within a @Configuration class to define Spring beans.

• The @Component annotation is used on classes to indicate that they are Spring components.

• The @Bean annotation allow...read more

Bean factory is a container for managing beans in Spring framework.

• Bean factory is responsible for creating, managing, and configuring beans in a Spring application.

• It uses inversion of control (IoC) to manage the beans.

• Beans are defined in a configuration file (XML or Java) and the bean factory instantiates them.

• Example: ApplicationContext is a type of bean factory in Spring framework.

Singleton is a design pattern that restricts the instantiation of a class to only one object.

• Ensures a class has only one instance and provides a global point of access to it.

• Commonly used in scenarios where a single instance of a class is needed, such as database connections or thread pools.

• Implemented by creating a static method to return the same instance of the class every time it is called.

The question covers various topics related to SpringBoot development.

• LinkedList vs ArrayList: LinkedList is better for frequent insertions/deletions, ArrayList is better for frequent access.

• Tomcat vs other application servers: Tomcat is a lightweight server, while others like JBoss are more feature-rich.

• AJAX JSON: AJAX is used to make asynchronous requests to the server, while JSON is a lightweight data interchange for...read more