Java interview question

1. What are the major features in different versions of Spring Framework?

Version

Logo

Feature

Spring 2.5

This version was released in 2007. It was the first version which supported annotations.

Spring 3.0

This version was released in 2009. Itmade full-fledged use of improvements in Java5 and also provided support to JEE6.

Spring 4.0

This version was released in 2013. This was the first version to provide full support to Java 8.

  • Spring is a powerful open source, application framework created to reduce the complexity of enterprise application development.
  • It is light-weighted and loosely coupled.
  • It has layered architecture, which allows you to select the components to use, while also providing a cohesive framework for J2EE application development.
  • Spring framework is also called the framework of frameworks as it provides support to various other frameworks such as Struts, Hibernate, Tapestry, EJB, JSF etc.

3. List the advantages of Spring Framework.

  • Because of Spring Frameworks layered architecture, you can use what you need and leave which you don’t.
  • Spring Framework enables POJO (Plain Old Java Object) Programming which in turn enables continuous integration and testability.
  • JDBC is simplified due to Dependency Injection and Inversion of Control.
  • It is open-source and has no vendor lock-in.

4. What are the different features of Spring Framework?

Following are some of the major features of Spring Framework :

  • Lightweight: Spring is lightweight when it comes to size and transparency.
  • Inversion of control (IOC): The objects give their dependencies instead of creating or looking for dependent objects. This is called Inversion Of Control.
  • Aspect oriented Programming (AOP): Aspect oriented programming in Spring supports cohesive development by separating application business logic from system services.
  • Container: Spring Framework creates and manages the life cycle and configuration of the application objects.
  • MVC Framework: Spring Framework’s MVC web application framework is highly configurable. Other frameworks can also be used easily instead of Spring MVC Framework.
  • Transaction Management: Generic abstraction layer for transaction management is provided by the Spring Framework. Spring’s transaction support can be also used in container less environments.
  • JDBC Exception Handling: The JDBC abstraction layer of the Spring offers an exception hierarchy, which simplifies the error handling strategy.

5. How many modules are there in Spring Framework and what are they?

There are around 20 modules which are generalized into Core Container, Data Access/Integration, Web, AOP (Aspect Oriented Programming), Instrumentation and Test.

Few Miscellaneous modules are given below:

  • Messaging — This module provides support for STOMP. It also supports an annotation programming model that is used for routing and processing STOMP messages from WebSocket clients.
  • This module provides support to integration with AspectJ.

6. What is a Spring configuration file?

A Spring configuration file is an XML file. This file mainly contains the classes information. It describes how those classes are configured as well as introduced to each other. The XML configuration files, however, are verbose and more clean. If it’s not planned and written correctly, it becomes very difficult to manage in big projects.

7. What are the different components of a Spring application?

A Spring application, generally consists of following components:

  • Interface: It defines the functions.
  • Bean class: It contains properties, its setter and getter methods, functions etc.
  • Spring Aspect Oriented Programming (AOP): Provides the functionality of cross-cutting concerns.
  • Bean Configuration File: Contains the information of classes and how to configure them.
  • User program: It uses the function.

8. What are the various ways of using Spring Framework?

Spring Framework can be used in various ways. They are listed as follows:

  1. As a Full-fledged Spring web application.
  2. As a third-party web framework, using Spring Frameworks middle-tier.
  3. For remote usage.
  4. As Enterprise Java Bean which can wrap existing POJOs (Plain Old Java Objects).

The next section of Spring Interview Questions is on Dependency Injection and IoC container.

9. What is Spring IOC Container?

At the core of the Spring Framework, lies the Spring container. The container c reates the object, wires them together, configures them and manages their complete life cycle. The Spring container makes use of Dependency Injection to manage the components that make up an application. The container receives instructions for which objects to instantiate, configure, and assemble by reading the configuration metadata provided. This metadata can be provided either by XML, Java annotations or Java code.

10. What do you mean by Dependency Injection?

In Dependency Injection, you do not have to create your objects but have to describe how they should be created. You don’t connect your components and services together in the code directly, but describe which services are needed by which components in the configuration file. The IoC container will wire them up together.

11. In how many ways can Dependency Injection be done?

In general, dependency injection can be done in three ways, namely :

In Spring Framework, only constructor and setter injections are used.

12. Differentiate between constructor injection and setter injection.

Constructor Injection vs Setter Injection

13. How many types of IOC containers are there in spring?

14. Differentiate between BeanFactory and ApplicationContext.

BeanFactory vs ApplicationContext

It is an interface defined in org.springframework.beans.factory.BeanFactory

It is an interface defined in org.springframework.context.ApplicationContext

It uses Lazy initialization

It uses Eager/ Aggressive initialization

It explicitly provides a resource object using the syntax

It creates and manages resource objects on its own

It doesn’t supports internationalization

It supports internationalization

It doesn’t supports annotation based dependency

It supports annotation based dependency

15. List some of the benefits of IoC.

Some of the benefits of IoC are:

  • It will minimize the amount of code in your application.
  • It will make your application easy to test because it doesn’t require any singletons or JNDI lookup mechanisms in your unit test cases.
  • It promotes loose coupling with minimal effort and least intrusive mechanism.
  • It supports eager instantiation and lazy loading of the services.

Let’s move on to the next section of Spring Interview Questions, that is Spring Beans Interview Questions.

16. Explain Spring Beans?

  • They are the objects that form the backbone of the user’s ap plication.
  • Beans are managed by the Spring IoC container.
  • They are instantiated, configured, wired and managed by a Spring IoC container

17. How configuration metadata is provided to the Spring container?

Configuration metadata can be provided to Spring container in following ways:

Originally published at https://www.techbotnet.com.

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