Top Spring Interview Questions and Answers for 2023 - IQCode

Overview of the Spring Framework

The Spring Framework is a popular Java framework that was created in 2003 by Rod Johnson. Its main goal is to simplify and speed up Java application development while also providing greater security for developers. Spring is open-source, lightweight, and a framework of frameworks, containing multiple frameworks such as Spring MVC, Spring Hibernate, Spring JDBC, and more. One of the key features of Spring is its infrastructural support for applications, allowing developers to focus purely on business logic and not on specific deployment environments. Applications built with Spring are reliable, scalable, and easy to create and maintain.


Spring Core, also known as Spring Framework Container, is at the heart of the Spring Framework. It provides the inversion of control (IoC) design pattern, allowing developers to build loosely coupled, flexible applications. It manages the creation and configuration of objects, enabling developers to focus on their feature-specific business logic instead of managing application objects.


In software engineering, the Inversion of Control (IoC) design pattern is used to invert the flow of control in a system. Spring Core provides a container to manage the dependencies between different components of an application. This enables developers to write code that is less tightly coupled, as the IoC container manages the creation of objects and their dependencies, rather than having the objects themselves handle these responsibilities.


Spring beans are Java objects that are managed by the Spring Framework's IoC container. They can be instantiated and configured with values, and then retrieved and used in your application as required. Spring beans can be registered using XML configuration files or with annotations.


Spring Framework offers several benefits, including:

- Simplified Java application development - Increased developer productivity - Greater security for developers - Improved testability of applications - Loosely coupled, flexible code architecture - Robustness and reliability in enterprise applications

In summary, Spring is a powerful Java framework that provides a host of benefits to developers. As a result, it has become a top choice for enterprise-level Java application development.

Key Features of the Spring Framework

The Spring Framework is a popular Java-based open-source application framework known for simplifying the development of enterprise-ready applications. Here are some of its key features:

- Inversion of Control (IoC) or Dependency Injection (DI) - Aspect-Oriented Programming (AOP) - Modularity - Portable - Transaction Management - Model-View-Controller (MVC)

These features of the Spring Framework make it highly scalable and customizable according to an application's requirements. Spring is also widely used for developing web applications, RESTful APIs, and microservices.

What is a Spring Configuration File?

In Spring, a configuration file is a file that defines how the different components of an application should be configured. It is usually an XML file that contains various tags and attributes that describe the configuration settings for beans, dependencies, and aspects. These files are used by the Spring IoC container to create and manage instances of objects throughout the lifetime of the application. Additionally, Spring also supports the use of Java-based configuration and Annotation-based configuration.

Explanation of IOC (Inversion of Control) Container

IOC (Inversion of Control) Container is a software design pattern that is used to manage object dependencies. It is known as a container because it contains instances of objects that can be retrieved and used throughout an application. The IOC container takes control of the construction and lifecycle of the objects. It helps in decoupling objects so that changes made to one object does not affect the other objects of the application. It allows the developer to focus on the core business logic of the application and decreases the amount of time spent on resolving dependencies.

Understanding Dependency Injection

Dependency Injection is a design pattern used in object-oriented programming to allow the creation of objects with their dependencies injected, rather than creating them inside the object itself. This means that instead of an object being responsible for creating and managing its dependencies, the responsibility is moved to a separate "injection" framework or container.

The basic idea behind Dependency Injection is to allow objects to be decoupled from their dependencies, thus promoting more flexible and modular code. This helps make code easier to maintain, extend, and test, as individual components can be swapped in and out without affecting the rest of the system.

For example, let's say we have a ClassA that requires an instance of ClassB to function properly. In a traditional approach, ClassA would have to create an instance of ClassB directly. With Dependency Injection, a separate framework or container will be responsible for injecting an instance of ClassB into ClassA, allowing ClassA to be more modular and easier to test.

Explanation of Constructor and Setter Injection

In object-oriented programming, dependency injection is a technique that involves passing objects or values to a class from outside to avoid tight coupling among classes. There are two types of dependency injection in Spring:

1. Constructor Injection: In this type of dependency injection, dependencies are provided to a class through its constructor. Once the constructor is invoked with the dependencies, the class is fully constructed and ready to use. Constructor injection is useful when you have a mandatory dependency that must be provided when the object is created.

2. Setter Injection: In this type of dependency injection, dependencies are provided to a class through its setters. If you do not provide dependencies using the setter, the class can still be instantiated with default values and setters can be used later to set these values. Setter injection is useful when you have optional dependencies that can be set any time after the object is created.

In summary, constructor injection is mandatory dependency injection and setter injection is optional dependency injection.

Understanding Spring Beans

In Spring Framework, a bean is an object that is instantiated, assembled, and managed by a Spring IoC (Inversion of Control) container. It is a replacement for factory design pattern and provides the advantage of making the application easy to configure and manage.

Basically, a Spring bean is a POJO (Plain Old Java Object) that is configured with metadata. This metadata is used by the Spring container to handle the bean lifecycle, including creation, initialization and destruction. Beans can be defined in a Spring configuration file or with annotations.

Beans support dependency injection (DI) which is a technique for achieving loose coupling between objects and managing their dependencies. Spring Framework provides various scopes for beans such as singleton, prototype, session, and request scopes, which enables the developer to control the lifecycle of beans.

In summary, Spring beans are the fundamental building blocks of a Spring application and provide a flexible, lightweight, and powerful way to manage objects in the application.

How Does Spring Container Receive Configuration Metadata?

In Spring framework, configuration metadata can be provided to the Spring container in various ways.

One way is to use XML-based configuration, where the configuration metadata is stored in an XML file and loaded into the Spring container using the XmlBeanFactory class. Another way is to use Java-based configuration, where the configuration metadata is provided in a Java class using annotations such as @Configuration and @Bean.

Additionally, Spring also provides support for Groovy-based configuration and Annotation-based configuration where annotations such as @Component, @Service, and @Autowired are used to provide configuration metadata to the Spring container.

In summary, Spring offers multiple ways to provide configuration metadata to the Spring container, giving flexibility and ease of use to the developers.

Bean Scopes in Spring Framework

In Spring Framework, there are five bean scopes available:

1. Singleton: A single bean instance is shared across the Spring container.

2. Prototype: A new bean instance is created each time a request for the bean is made.

3. Request: A single bean instance is created and used for each HTTP request.

4. Session: A single bean instance is created and used for each HTTP session.

5. Global Session: A single bean instance is created and used for each global HTTP session in a portlet context.

Note: It is important to choose the appropriate scope for a bean based on its intended use within your application in order to optimize performance and reduce memory usage.

Understanding Spring Bean Life Cycle in the Bean Factory Container

In Spring, a bean is an object that is initialized and managed by the Spring IoC container. The life cycle of a Spring bean can be divided into several phases, including:

1. Instantiation: The Spring container creates a new instance of the bean by calling the bean's no-argument constructor or a factory method.

2. Population of Properties: The Spring container populates the bean's properties using dependency injection, applying configured values for the bean's properties and references to other beans.

3. Pre-Initialization: The bean's init method is called to perform any necessary initialization steps before the bean is ready for use.

4. In Use: Once the bean is initialized, it can be used normally.

5. Destruction: When the container decides to remove a bean, it calls the bean's destroy method to release any resources held by the bean.

Understanding the bean life cycle in Spring is crucial for creating and managing beans effectively.

Understanding Bean Wiring

Bean wiring is a process in Spring Framework where the dependencies of an object instance are set by Spring. This is achieved through configuration metadata that describes how different beans are initialized and wired together. Spring uses dependency injection to achieve this, which allows for loose coupling between components and makes it easier to change the behavior of an application by swapping out different dependencies. Overall, bean wiring is a critical part of the Spring Framework as it enables developers to easily configure and manage complex applications.

Understanding Autowiring in Spring Framework and Its Different Modes

Autowiring in Spring is a feature that allows automatic injection of objects and dependencies into a Spring-managed bean. This eliminates the need for manual configuration of bean dependencies that can be time-consuming and prone to errors. Autowiring is enabled by default in Spring, but it can be disabled or configured to work in one of the following modes:

1. By Type: In this mode, Spring searches for a bean of the required type and injects it into the requesting bean. If there are multiple beans of the same type, the autowiring process fails, and the developer has to specify which bean to use.

2. By Name: In this mode, Spring looks for a bean with the same name as the required property and injects it into the requesting bean. If there is no bean with the same name, the autowiring process fails.

3. By Constructor: In this mode, Spring attempts to identify the constructor that matches the types of the required parameters and injects the appropriate beans into the constructor.

4. By Qualifier: In this mode, Spring looks for a bean that matches both the type and the qualifier value specified in the @Qualifier annotation.

5. No Autowiring: In this mode, no dependency injection occurs, and the bean has to be configured manually.

Overall, autowiring in Spring is a powerful feature that can greatly simplify bean configuration and dependency injection. However, it's essential to use it judiciously and appropriately for optimal performance and maintainability.

Limitations of Autowiring

Autowiring in Spring has the following limitations:

- It only works with public methods.
- It may not be clear which implementation is being used when multiple implementations of an interface are present.
- It can only be used with objects that have a default constructor or one that has been marked with the @Autowired annotation.
- It may lead to too many dependencies being injected, making the code difficult to read and maintain.

Therefore, it's important to carefully consider whether autowiring is the most appropriate solution for a particular use case, and to use it judiciously to avoid potential issues in your Spring application.

Spring Boot Interview Questions

Spring Boot

is a framework built on top of the


framework. It is designed to simplify the process of creating and deploying standalone, production-grade Spring-based applications with minimal configuration. Spring Boot provides out-of-the-box support for embedded containers such as Tomcat, Jetty, and Undertow, and comes with several tools and pre-configured settings to get started quickly. In essence, Spring Boot makes it easy to create Spring-based applications that are production-ready, with minimal effort and configuration.

Advantages of Using Spring Boot for Application Development

Spring Boot is a popular Java framework that offers many advantages for application development. Here are some of the key benefits of using Spring Boot:

  1. Easy Setup: Spring Boot allows for a quick and easy setup of new Spring applications. It eliminates the need for XML configuration files and reduces the amount of boilerplate code needed to get an application up and running.

  2. Integrated Dependencies: Spring Boot comes with many pre-configured dependencies that streamline application development and make it easier to integrate with other systems and services.

  3. Embedded Servers: Spring Boot includes embedded servers, such as Tomcat, Jetty, and Undertow, which eliminates the need for separate server installation and configuration.

  4. Auto-configuration: Spring Boot's auto-configuration feature detects and configures components based on the classpath and other settings. This saves development time and reduces the risk of configuration errors.

  5. Production-Ready: Spring Boot includes features that make applications secure, reliable, and easy to deploy in production environments. This includes support for metrics, health checks, logging, and more.

In summary, Spring Boot simplifies and accelerates the development of Java applications by offering easy setup, integrated dependencies, embedded servers, auto-configuration, and production-ready features.

Differences Between Spring and Spring Boot

Spring is a popular Java framework used to build enterprise-level web applications. It provides a wide range of features and functionalities, including dependency injection, aspect-oriented programming, and integrated security.

Spring Boot is an extension of Spring that focuses on making it easier and quicker to set up and configure Spring-based applications. It provides a variety of auto-configurations and defaults to minimize the amount of boilerplate code that needs to be written.

Here are some key differences between Spring and Spring Boot:

  • Spring requires more manual configuration and set up, while Spring Boot aims to automate as much of it as possible.
  • Spring is highly customizable, allowing developers to customize every aspect of their application, while Spring Boot provides fewer options and sets many defaults.
  • Spring is a more comprehensive framework, offering a wide range of features and integrations, while Spring Boot is more focused on simplifying the development process.

Overall, while Spring is a powerful and flexible framework with a steep learning curve, Spring Boot is a more streamlined and efficient way to build Spring-based applications.

// Sample Spring Boot Application
public class MyApp {
  public static void main(String[] args) {, args);

  public class MyController {
    public String helloWorld() {
      return "Hello, World!";

Features of Spring Boot

Spring Boot is a popular Java framework that provides many features to simplify the development of Java-based applications. Some of the notable features of Spring Boot are:

  1. Easy Configuration: Spring Boot provides a simple and easy-to-use configuration system that eliminates the need for boilerplate code and reduces the overall development time.

  2. Starter Dependencies: Spring Boot includes a range of starter dependencies that help developers to quickly set up and configure various components and libraries.

  3. Auto-configuration: Spring Boot has powerful auto-configuration capabilities that automatically configure many of the framework's features based on the application's dependencies.

  4. Production-ready features: Spring Boot provides many production-ready features, such as health checks, metrics, and distributed tracing, out-of-the-box.

  5. Embedded servers: Spring Boot includes embedded servers, such as Tomcat, Jetty, and Undertow, that simplify the deployment of applications.

  6. Actuator: Spring Boot Actuator provides a range of endpoints for monitoring and managing the application, such as health, metrics, and info.

Overall, Spring Boot offers an opinionated approach to application development and helps developers to create robust and scalable applications with minimal effort.

Internal Functionality of @SpringBootApplication Annotation

The @SpringBootApplication annotation in Spring Boot is a combination of three other annotations: @Configuration, @EnableAutoConfiguration, and @ComponentScan.

When @SpringBootApplication is used on a class, it initializes the Spring application context and enables auto-configuration and component scanning.

@Configuration annotation is used for configuration classes while @ComponentScan scans the package and its subpackages to look for Spring-managed components, such as beans.

@EnableAutoConfiguration enables automatic configuration of the Spring application based on the classpath dependencies of the project.

Overall, the @SpringBootApplication annotation simplifies the process of setting up a Spring Boot application by providing a convenient way to enable necessary features.

Effects of Running a Spring Boot Application as a Java Application

Running a Spring Boot application as a Java Application means that it will be executed as a standard Java program. This method has a few effects:

1. It requires the user to have access to the command line or an IDE to run the program. 2. The user needs to manually configure a server to deploy the application on. 3. Any changes to the code require the application to be recompiled and redeployed manually.

Overall, running a Spring Boot application as a Java application is not the most efficient way to deploy and manage the application, especially for larger projects with frequent changes. Instead, it is recommended to use Spring Boot's built-in tools and features such as the Spring Boot CLI or a build tool like Maven or Gradle to package and run the application as a standalone executable JAR file.

Understanding Spring Boot's Dependency Management System

Spring Boot includes a powerful dependency management system that simplifies the management of dependencies in your project. It makes use of Maven and Gradle to manage your dependencies, allowing you to easily import supported libraries and other dependencies into your project.

By using Spring Boot's dependency management, you can avoid version conflicts between different libraries and ensure that all dependencies are compatible with each other. This can save you time and effort in resolving dependency-related issues and allow you to focus on writing your application logic.

Possible Sources of External Configuration

There are various sources of external configuration that can be utilized in a software application. These sources include but are not limited to:

  • Properties files
  • XML configuration files
  • Environment variables
  • Command line arguments
  • Database tables or records

By providing external configuration options, developers can make their software more flexible and adaptable to different environments and use cases. It also allows for easier maintenance and updates, as configuration changes can be made without having to modify and rebuild the entire application.

Modifying the Default Port of the Embedded Tomcat Server in Spring Boot

Yes, we can easily modify the default port of the embedded Tomcat server in Spring Boot. By default, the embedded Tomcat server runs on the port number 8080. To change the default port, we just need to set a new value for the "server.port" property in the "" file.

For example, to run the server on port number 9090, add the following line to the "" file:


We can also set the port number programmatically by adding the following code to the main class:

SpringApplication.setDefaultProperties(Collections.singletonMap("server.port", "9090"));

By modifying the default port of the embedded Tomcat server, we can avoid port conflicts with other applications running on the same server.

Excluding Packages Without Using the BasePackages Filter

To exclude packages in Java without using the BasePackages filter, you can utilize the excludeFilters attribute of the @ComponentScan annotation. This attribute accepts an array of Filter objects that specify packages or classes to exclude.

Here's an example code snippet that demonstrates how to exclude a package using excludeFilters:


    basePackages = "com.example",
    excludeFilters = @ComponentScan.Filter(
        type = FilterType.REGEX,
        pattern = "com.example.excludePackage.*"

In the above example, the @ComponentScan annotation is used with the excludeFilters attribute to exclude the "com.example.excludePackage" package from the component scan. The REGEX filter type is used to specify the pattern to match against the package names.

Disabling Specific Auto-Configuration Class in Spring Boot

In Spring Boot, you can disable specific Auto-Configuration classes by using the `@SpringBootApplication` annotation and its `exclude` parameter.

For example, let's say you want to disable the auto-configuration class `XyzAutoConfiguration`. You would create a configuration class and exclude the `XyzAutoConfiguration` class as shown below:

@SpringBootApplication(exclude = { XyzAutoConfiguration.class })
public class MyApplication {
   public static void main(String[] args) {, args);

By adding `exclude` parameter in `@SpringBootApplication` annotation with the `XyzAutoConfiguration.class` entry, we are disabling the auto-configuration class `XyzAutoConfiguration`.

This way you can disable specific auto-configuration classes in Spring Boot.

Disabling the Default Web Server in a Spring Boot Application

Yes, it is possible to disable the default web server in a Spring Boot application. This can be achieved by setting the `spring.main.web-application-type` property to `NONE` in the file. This will prevent the application from starting the embedded web server.

However, disabling the web server may not be suitable for all applications as it can limit the functionalities of the application that require web access. It is recommended to carefully consider the implications before disabling the default web server.

Explanation of the @RequestMapping and @RestController Annotations in Spring Boot

In Spring Boot, the @RequestMapping annotation is used to map a URI (Uniform Resource Identifier) to a specific method in a controller class. This allows the application to handle requests made by clients and return an appropriate response.

The @RestController annotation, on the other hand, is used to indicate that the methods within a controller class are capable of producing a response in a RESTful format. It is essentially a combination of the @Controller and @ResponseBody annotations.

Together, these annotations enable developers to create a web application that supports RESTful services. They allow the application to map URIs to specific methods, and also to produce responses that can be easily consumed by clients.

Interview Questions: Spring AOP

One of the interview questions related to Spring is, "What is Spring AOP?" Spring AOP, or Aspect-Oriented Programming, is a framework that allows developers to implement cross-cutting concerns in their software. Cross-cutting concerns refer to the functionalities that are not the core responsibility of the software but are necessary for its functioning, such as logging, tracing, or caching. Spring AOP provides a way to separate the cross-cutting concerns from the business logic, making the code cleaner and easier to manage.

//Example of Spring AOP:
public class LoggingAspect {
   @Before("execution(* com.example..*(..))")
   public void logBefore(JoinPoint joinPoint) {
      System.out.println("Logging before method: " + joinPoint.getSignature().getName());
   @After("execution(* com.example..*(..))")
   public void logAfter(JoinPoint joinPoint) {
      System.out.println("Logging after method: " + joinPoint.getSignature().getName());

The above example shows a basic logging aspect that will execute before and after all methods in the package com.example. The @Aspect annotation marks the class as an aspect, and the @Before and @After annotations mark the methods that will execute before and after the target methods, respectively.

Understanding Advice in Spring and its Types

In Spring, advice refers to the additional functionality that can be added to a method during the program's execution. There are different types of advice available in Spring AOP, which are:

1. Before Advice: This advice type executes before the advised method is invoked. 2. After Returning Advice: This advice type executes after the execution of the advised method, only if it completes successfully. 3. After Throwing Advice: This advice type executes when an exception is thrown during the execution of the advice method. 4. After Advice: This advice type executes after the completion of the advised method, regardless of its outcome. 5. Around Advice: This advice type surrounds the advised method, thereby allowing the user to execute custom code before and after the advised method is executed.

By using these different types of advice, we can control the flow of execution during the program's runtime in Spring.

Explaining the Spring AOP Proxy Pattern

The Spring AOP proxy pattern is a design pattern used in Spring Framework that makes use of dynamic proxies to apply aspects to target objects. It allows developers to modularize behavior that cuts across multiple classes and apply them selectively to needed objects with the help of pointcuts. In other words, this pattern provides an easy way to apply cross-cutting concerns to an existing application without modifying its code.

Classes in Spring JDBC API

In Spring JDBC API, some of the important classes are:


: A class that simplifies the use of JDBC and helps in executing SQL statements.


: A class that simplifies inserting data into a database.


: A class that simplifies calling stored procedures in a database.


: A class that uses named parameters instead of '?' placeholders in SQL statements.


: A class that represents a set of data rows returned by a SQL query.


: An interface that maps a row returned by a SQL query to a Java object.


: An interface that provides named parameters for a SQL query.


: An interface that provides a standard method of getting a connection to a database.

How to retrieve records using Spring JdbcTemplate?

To fetch records using Spring JdbcTemplate, we can follow the below steps in our Java code:

// Import necessary packages import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.datasource.DriverManagerDataSource; import javax.sql.DataSource; import java.util.List;

public class DatabaseAccess { // Create a datasource object to connect with the database private DataSource dataSource;

// Create a JdbcTemplate object private JdbcTemplate jdbcTemplate;

// Constructor to initialize datasource and jdbcTemplate objects public DatabaseAccess() { DriverManagerDataSource dataSource = new DriverManagerDataSource(); dataSource.setDriverClassName("com.mysql.jdbc.Driver"); dataSource.setUrl("jdbc:mysql://localhost:3306/mydatabase"); dataSource.setUsername("root"); dataSource.setPassword(""); this.dataSource = dataSource; this.jdbcTemplate = new JdbcTemplate(dataSource); }

// Method to fetch all records from the database table public List getAllEmployees() { String sqlQuery = "SELECT * FROM employee"; List employees = jdbcTemplate.query(sqlQuery, new EmployeeMapper()); return employees; }

// EmployeeMapper class to map ResultSet with Employee object private static final class EmployeeMapper implements RowMapper { @Override public Employee mapRow(ResultSet resultSet, int rowNum) throws SQLException { Employee employee = new Employee(); employee.setId(resultSet.getInt("id")); employee.setName(resultSet.getString("name")); employee.setAge(resultSet.getInt("age")); employee.setDepartment(resultSet.getString("department")); return employee; } } }

In the above code, we first create a datasource object to connect with the database, and then use that to create a JdbcTemplate object. We can then use this object to execute our SQL queries and retrieve the results.

In the getAllEmployees() method, we have written a SQL query to select all records from the employee table. We use the jdbcTemplate object to execute this query and map the ResultSet with the Employee object using the EmployeeMapper class. Finally, we return the list of all employees fetched from the database.

Overview of Hibernate ORM Framework

Hibernate is an Object-Relational Mapping (ORM) framework for Java that simplifies the data access layer of applications. It provides a way to map Java objects to relational database tables along with a convenient API for querying and persisting data. Hibernate eliminates the need for writing tedious JDBC code and allows developers to focus on the business logic of their applications. Overall, Hibernate is a powerful and popular tool for creating efficient and scalable Java applications.

Two Ways to Access Hibernate Using Spring

There are two ways to access Hibernate using Spring framework: 1. Using HibernateTemplate class: This class simplifies Hibernate data access code and eliminates the need for repetitive code. It provides methods for common Hibernate operations, such as persist, merge, delete, load, and find.

2. Using SessionFactory class: This class provides direct access to the Hibernate SessionFactory, and allows for more fine-grained control over Hibernate operations. It is more flexible than HibernateTemplate, but requires more configuration and coding.

Both approaches are viable options for accessing Hibernate with Spring, and the choice between them depends on the specific needs of the application.

Explanation of the Hibernate Validator Framework

The Hibernate Validator Framework is a Java-based framework for performing constraint validation on objects. It allows developers to annotate their JavaBean classes with constraints and then automatically validates the objects based on those constraints. This helps to ensure that the objects are consistent with the business rules and data integrity requirements of the application. The Hibernate Validator Framework provides a set of predefined constraints, as well as the ability to create custom constraints. It is commonly used in Java Enterprise Edition (JEE) applications and integrates well with other JEE technologies such as Spring and JPA.

Understanding the HibernateTemplate Class

The HibernateTemplate class is a part of the Spring Framework's ORM (Object Relational Mapping) module that provides a simplified approach to interact with the Hibernate ORM tool. It encapsulates Hibernate exceptions and manages transactions, simplifying the usage of the Hibernate API. The HibernateTemplate class provides a convenient and lightweight wrapper for Hibernate operations, simplifying the underlying data access code.

Essentially, the HibernateTemplate class is a central class of the Hibernate integration layer within the Spring Framework, allowing developers to benefit from the functionality of both technologies in a unified way.

Spring MVC Framework

The Spring MVC (Model-View-Controller) framework is a popular Java web application framework used to develop enterprise-level web applications. It follows a design pattern that separates the application into three interconnected parts: Model (data), View (user interface), and Controller (logic). This separation allows for isolation of concerns and supports modular development, making it easier to maintain and modify the application. The Spring MVC framework provides a rich set of features such as dependency injection, inversion of control, and support for RESTful web services, making it a popular choice for web application development.

Benefits of Spring MVC Framework over other MVC Frameworks

The Spring MVC framework has several benefits over other MVC frameworks:

  • Modularity: Spring MVC is highly modular and allows developers to pick and choose the components to use in their applications as per requirement.
  • Inversion of Control (IoC): Spring MVC supports IoC design pattern, which helps in avoiding the hardcoding and makes the code more maintainable and testable.
  • Testability: Spring MVC is highly testable due to its loose coupling and modular design.
  • Flexibility: Spring MVC provides developers with the freedom to integrate third-party libraries effortlessly.
  • Performance: With its flexible caching mechanism and optimized performance, Spring MVC can efficiently handle high traffic and large-scale enterprise applications.

With these benefits, Spring MVC is a popular choice for building web applications, especially in the enterprise domain.

// Example code demonstrating the use of Spring MVC to handle HTTP requests and render HTML views

Understanding the Spring MVC architecture

In the Spring MVC framework, the DispatcherServlet acts as the front controller. It receives all the incoming requests and delegates them to the respective controllers for further processing. The controllers then handle the requests and generate the appropriate responses to be sent back to the client.

The DispatcherServlet is responsible for mapping each request to the appropriate controller based on the request URL and controller mappings. It also manages several helper components such as the view resolver and handler mappings.

The Spring MVC framework uses a layered architecture to organize the application components. The model represents the application data and business logic, the view represents the user interface, and the controller sits between the model and view layers to handle the user requests and act as a mediator.

Overall, the Spring MVC architecture provides a robust and flexible framework for building web applications, allowing developers to easily create and maintain scalable and efficient applications.

Understanding the View Resolver pattern in Spring MVC

In Spring MVC, the View Resolver pattern is used to map view names to actual view implementations. It is significant because it separates the view implementation details from the controller logic. This ensures reusability and flexibility in the application design.

The view resolver strategy involves three components: View Resolver, View and View Resolver Chain. When a request is made to a controller, it returns a view name. This name is resolved by the View Resolver, which returns a View implementation. The View then renders the response and returns it to the client.

Using this pattern, we can easily switch between different view technologies, such as JSP, Thymeleaf, or any other custom view technology. It also allows us to modify the view name resolution strategy without changing the controller code.

Overall, the View Resolver pattern provides an efficient and flexible way to handle views in a Spring MVC application.H3 tag

What is the Purpose of the @Controller Annotation in Java Spring?

P tag

The @Controller annotation in Java Spring is used to indicate that a particular class serves the role of a controller. By adding this annotation to a class, we can tell Spring that the given class should be treated as a controller and it will be able to handle HTTP requests. In other words, this annotation is used to mark a class as a Spring MVC controller, much like how the @RestController annotation can be used to indicate that a particular controller class is a RESTful web service.

Creating a Controller without @Controller or @RestController Annotations

Yes, it's possible to create a controller without using the @Controller or @RestController annotations.

To do so, we can simply define a regular class and use the @RequestMapping annotation on the methods that should handle our requests. Here's an example:

public class MyController {

   public String hello() {
      return "Hello world!";


In the above example, we've defined a class called "MyController" that handles requests to "/hello". The method "hello()" returns a String, which will be the response sent back to the client.

Once our class is defined, we can configure it in our Spring configuration file by creating a bean for it:

<bean id="myController" class="com.example.MyController"/>

With this configuration in place, our controller will be available to handle requests. Note that we can also use dependency injection to inject any services that our controller may need.

Understanding ContextLoaderListener and Its Functionality

The ContextLoaderListener is a class provided by the Spring Framework that implements the ServletContextListener interface. It is used to load and configure a Spring application context.

When a web application starts, the ContextLoaderListener creates and initializes a single instance of the Spring application context, which can be used to manage beans and perform other tasks within the web application. The context is also configured with servlet filters, servlets, and listeners defined in the Spring application context file.

By using the ContextLoaderListener, the application context can be loaded before any servlets or filters are initialized. This can be helpful in scenarios where there are dependencies between servlets and filters and where certain beans need to be initialized first.

Overall, ContextLoaderListener is a powerful tool that simplifies the deployment of Spring-based web applications, making it easy to manage and configure the application context within the web application.

Differences between @RequestParam and @PathVariable Annotations

In Spring MVC,




are two annotations used to extract values from the incoming HTTP request.
Here are the differences between them:

  • @RequestParam

    is used to retrieve query parameters or form data from the request whereas


    is used to retrieve values from the URI path.

  • @RequestParam

    is optional, whereas


    is mandatory and must be provided in the request.

  • @RequestParam

    can be used for simple key-value pairs, and it supports parameters with default values.


    , on the other hand, is used to extract values from the URI path.

Example Usage:


public String getProduct(@PathVariable Long id, @RequestParam String name) {

// method implementation


In this example, the


annotation specifies a URI template with a path variable


and the


annotation specifies a query parameter 'name'. The method parameter

@PathVariable Long id

is used to extract the value from the URI path and the

@RequestParam String name

is used to extract the value from the query parameter.

What is the Model in Spring MVC?

In Spring MVC, the Model is responsible for holding the data that is to be displayed to the user. It represents the data in a way that is easily consumed by the view layer. The Model interfaces with the business logic layer and retrieves the necessary data. Once the data is received, the Model populates it and sends it back to the Controller, which then forwards it to the View for display. The Model can be represented by a plain Java object, a Map, or a List. It is often used in conjunction with Spring's annotation-based data binding and validation features to provide a seamless and consistent user experience.

Explanation of the @Autowired Annotation in Java

In Java, the @Autowired annotation is used to automatically wire or inject a dependency into a class. This means that when a class requires an object of another class to perform a task, @Autowired can be used to automatically inject an instance of that class without the need for explicit instantiation. This reduces the amount of boilerplate code needed and makes the code more maintainable.

For example, consider a service class that requires an object of a repository class to perform some database operations. Instead of manually instantiating the repository object, @Autowired can be used to inject it automatically:


@Service public class MyService {

@Autowired private MyRepository myRepository;

// other methods that use myRepository }

Here, the @Autowired annotation is used on the MyRepository object. Spring framework will automatically instantiate and inject the required MyRepository object into the service class when it is needed.

Overall, the @Autowired annotation simplifies the process of dependency injection and enhances the readability and maintainability of the code.

Understanding the @ModelAttribute Annotation in Spring MVC

The @ModelAttribute annotation in Spring MVC is used to bind a method parameter or method return value to a named model attribute and then add it to the model object. This means that the @ModelAttribute annotation allows you to set default values for model attributes and bind form values to model attributes.

When annotated on a method parameter, it indicates that the parameter should be retrieved from the model. When annotated on a method, it indicates that the model attribute returned from the method should be added to the model.

For example, let's say you have a form that a user can fill out to submit their contact information. You can use the @ModelAttribute annotation to create a model attribute for this form data and then use it to populate an object in your controller method.


public String showContactForm(@ModelAttribute("contact") ContactForm contactForm) {
    return "contact-form";

public String submitContactForm(@ModelAttribute("contact") ContactForm contactForm) {
    // process form data and save to database
    return "confirmation-page";

In the code above, the `@ModelAttribute` annotation is used to bind the `ContactForm` object to the "contact" attribute in the model.

Overall, the @ModelAttribute annotation plays a key role in Spring MVC by allowing you to easily bind data between the model and the controller, and by providing a way to set default values for model attributes.

Importance of web.xml in Spring MVC

In a Spring MVC application, the web.xml file serves as the deployment descriptor. It helps the application server to understand the structure and configuration of the web application.

The web.xml file in Spring MVC contains information about the servlets, filters, and listeners that are part of the DispatcherServlet's runtime environment. This configuration file allows developers to define URL mappings, security configurations, and other important settings.

Without the web.xml file, the DispatcherServlet would have no information about the application's configuration and would not be able to function properly. Therefore, it is essential to have a properly configured and maintained web.xml file in any Spring MVC application.

Types of Dependency Injection in Spring MVC

In Spring MVC, there are two types of Dependency Injection:

1. Constructor Injection: This type of injection is done through the constructor of a class. The required dependencies are passed through the constructor arguments.

2. Setter Injection: This type of injection is done through setter methods of a class. The required dependencies are set through the setter methods.

Both types of injection allow for loose coupling between classes and make it easier to perform unit testing.

Importance of Session Scope

Session scope is important in web development as it allows for the persistence of data across multiple requests made by the same user. This means that if a user were to navigate away from a webpage and then return, any information they had previously entered or actions they had taken would still be available.

This can be very useful for things like user authentication and shopping cart functionality, as it allows the application to keep track of which user is currently logged in and what items they have added to their cart.

In addition, utilizing session scope can improve the overall performance of an application by reducing the number of requests made to the database and improving the speed at which the application can provide the user with a personalized experience.

Overall, utilizing session scope can help to create a more seamless and user-friendly experience for website visitors.

The Importance of @Required Annotation

The @Required annotation is used in Spring Framework to indicate that a particular bean property must be set in the Spring configurations XML file. It ensures that the required dependencies are injected into the bean property accurately during the initialization of the bean. If the required property is not set, a BeanInitializationException is thrown. Thus, the @Required annotation helps to enforce the required dependencies and improve the dependability of the Spring beans.

Differences between @Autowired and @Inject Annotations

In Java, both @Autowired and @Inject annotations can be used for Dependency Injection. However, there are a few differences between these two annotations:

1. Origin: @Autowired is a Spring Framework annotation, while @Inject is a standard Java annotation that was introduced in JSR-330.

2. Package: @Autowired is part of the org.springframework.beans.factory.annotation package, while @Inject is part of the javax.inject package.

3. Configuration: By default, @Autowired is configured to be required whereas @Inject is not. However, this can be changed using the required attribute in @Inject.

4. Implementation: Both @Autowired and @Inject will try to match the dependency type with an available bean in the container. However, @Inject is more flexible in this regard since it allows for custom implementation of this behavior by extending its @Qualifier annotation.

5. Supported by: @Autowired is supported exclusively by Spring Framework, while @Inject is supported by all Dependency Injection frameworks that conform to the JSR-330 standard.

Therefore, the choice between using @Autowired or @Inject depends on specific project requirements and context.

Singleton Beans and Thread Safety

In Java, singleton beans are thread-safe by default. This means that only one instance of a singleton bean is created per application context. As a result, multiple threads can access and manipulate the same instance of the singleton bean concurrently without creating any data inconsistency issues.

However, if a singleton bean has any mutable instance variables or state that can be modified by multiple threads concurrently, it is important to ensure that access to these variables or state is synchronized to avoid potential thread-safety issues.

Achieving Thread-Safety in Beans

To achieve thread-safety in beans, you can use synchronized methods or blocks to ensure that only one thread can access the bean at a time. Another option is to use the ThreadLocal class to create a separate instance of the bean for each thread. This ensures that each thread has its own copy of the bean and can access it without interference from other threads. Additionally, you can use the volatile keyword to ensure that changes to the bean are visible to all threads immediately. By implementing these techniques, you can ensure that your beans are thread-safe and can be accessed by multiple threads simultaneously without any issues.H3 tag: Significance of @Repository Annotation in Java

In Java, the @Repository annotation is used to indicate that a particular class is a repository, which means it is responsible for managing the data access and storage operations. This annotation serves as a marker for the Spring framework to identify the class as a repository component and perform dependency injection and exception translation on it.

The @Repository annotation is a specialization of the @Component annotation and is used specifically for classes that work with persistent data storage mechanisms, such as databases. It provides a standardized way to manage data access code, separates data access logic from business logic, and simplifies code maintenance and testing.

Instantiation of Dispatcher Servlet

In a typical Java web application that uses Spring, the DispatcherServlet is instantiated automatically by the Spring container when the application context is created. The instantiation is done based on the configuration provided in the web.xml file, where the servlet-mapping tag maps the URL pattern to the DispatcherServlet. Once the DispatcherServlet is instantiated, it acts as a front controller and handles all incoming requests for the web application.

Loading the Root Application Context in Spring MVC

In Spring MVC, the root application context is loaded by the ContextLoaderListener class. This class listens to the ServletContextEvent and creates a new instance of the application context. The ContextLoaderListener is usually configured in the web.xml file as a listener.

The root application context is responsible for managing the entire lifecycle of the Spring MVC application, including the creation and management of the various beans. It is also responsible for loading the JDBC templates, hibernate session factories, and other common beans that can be shared across all the servlets.

To load the root application context, you first need to create an XML file that defines the beans that you want to load. This file will typically be named something like applicationContext.xml. Once you have created this file, you need to configure the ContextLoaderListener in your web.xml file by adding the following code snippet:


This will create a new instance of the root application context and load the beans defined in your applicationContext.xml file. You can then access these beans from any servlet in your application by using the getBean method of the ApplicationContext interface.

In summary, the ContextLoaderListener class is responsible for loading the root application context in Spring MVC. This context is responsible for managing the entire lifecycle of the application and loading the common beans that can be shared across all servlets.

Understanding the Spring MVC Flow

The flow in Spring MVC begins with an incoming request from a client, which is first received by the DispatcherServlet. This servlet acts as the front controller, and is responsible for processing all incoming requests. After receiving the request, the DispatcherServlet consults a list of HandlerMappings to determine which Controller should be used to handle the request.

Once the appropriate Controller has been identified, the DispatcherServlet forwards the request to it. The Controller then processes the request and returns a ModelAndView object to the DispatcherServlet, which contains the model data as well as a logical view name. The DispatcherServlet then consults a list of ViewResolvers to determine which View should be used to render the response.

Finally, the View is rendered and the response is sent back to the client. It's important to note that the flow in Spring MVC is highly configurable, and each step in the process can be customized to suit the needs of the application.

//Sample code for DispatcherServlet configuration



Source of Model Access from View in MVC Architecture

In the MVC architecture, the access to the Model from the View is typically facilitated through the Controller. The Controller receives input from the View and then updates the Model accordingly. The updated Model is then sent back to the Controller, which in turn updates the View with the new data. This process ensures that the Model and View remain completely independent of each other, with the Controller acting as the intermediary.

Reasons for Using BindingResult in Spring MVC

In Spring MVC, BindingResult is used to store and access the errors encountered during the validation of form submissions. The main reasons for using BindingResult are:

1. To handle form validation errors gracefully and display them to users in a user-friendly way. 2. To prevent the application from crashing due to validation errors. 3. To allow developers to access and handle validation errors programmatically.

Overall, BindingResult is an important tool for ensuring that user input is properly validated and that errors are handled effectively in Spring MVC applications.

Explanation of Spring Interceptors

Spring Interceptors are components in the Spring framework that allow developers to intercept HTTP requests and responses. They provide a means to add additional processing logic before and after the request is handled by the controller. Essentially, an interceptor is executed before the controller method is called and after the controller method finishes execution. Interceptors can be used for a variety of tasks, including logging, authentication, authorization, session management, and caching.

To implement an interceptor in Spring, developers need to create a class that implements the HandlerInterceptor interface. This interface contains three methods:

- preHandle(HttpServletRequest request, HttpServletResponse response, Object handler): This method is called before the handler method is executed by the controller. It allows developers to perform pre-processing logic, such as checking for authentication or logging the request.

- postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView): This method is called after the handler method finishes execution, but before the view is rendered. It allows developers to modify the ModelAndView object or add additional attributes to the model.

- afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex): This method is called after the view is rendered and allows developers to perform cleanup tasks, such as closing resources or logging the response.

Once the interceptor class is created, it needs to be registered with the Spring framework by either implementing the WebMvcConfigurer interface or extending the WebMvcConfigurationSupport class.

Interceptors can be configured to apply globally to all requests, or to specific requests based on path patterns or URL mappings. Overall, Spring Interceptors provide developers with a flexible and powerful way to modify and add functionality to HTTP requests and responses in their applications.

Do I Need to Include spring-mvc.jar in the Classpath if spring-core is Already Present?

When using Spring Framework, it is not necessary to include spring-mvc.jar in the classpath if spring-core is already present. This is because spring-mvc.jar is a part of the Spring Framework and is dependent on spring-core. Therefore, including spring-core is sufficient.

Differences between the and tags in HTML

In HTML, both the and tags are used to emphasize text, but there are some differences between them.

The tag is used to indicate text that is in an alternate voice or mood, or to mark text that is a technical term, a phrase from another language, or a fictional character's thoughts. It does not necessarily convey emphasis.

The tag, on the other hand, is used to emphasize text and indicate stress or importance. It should be used for text that requires emphasis due to its significant meaning in the context of the sentence or paragraph.

In terms of styling, the tag typically renders the text in italic font, while the tag renders it in bold or strong font.

It's important to note that the usage of these tags should be based on semantic meaning rather than their visual appearance. In other words, use when indicating alternate voice or mood, technical terms, etc., and use when emphasizing the significance of text.

Form Data Validation in Spring Web MVC Framework

In Spring Web MVC Framework, form data validation is performed using the standard validation annotations provided by Java Bean Validation API. These annotations can be used to enforce constraints on the input data received from the user.

To validate the form data, we first create a model class with the required fields and annotate them with appropriate validation constraints. For example, we can use the @NotNull annotation to ensure that a field is not empty, @Min and @Max to specify a range of allowed values, and @Email to validate an email address.

	public class User {
	    private String username;
	    private String email;
	    private int age;
	    // Getters and setters

Next, in the controller class, we can use the @Valid annotation to trigger the validation process and the BindingResult class to collect any errors that occurred during validation.

	@RequestMapping(value = "/register", method = RequestMethod.POST)
	public String register(@Valid User user, BindingResult result) {
	    if (result.hasErrors()) {
	        // Handle validation errors
	        return "register-form";
	    } else {
	        // Save user to database
	        return "success-page";

In the example above, if the input data fails any of the validation constraints, the error messages will be added to the BindingResult object. We can then use these error messages to display feedback to the user or take appropriate action.

Overall, Spring Web MVC Framework provides powerful and flexible support for form data validation, making it easy to ensure that our applications receive valid input.

Obtaining ServletConfig and ServletContext Objects in Spring Beans

When working with Spring beans, it is possible to obtain the ServletConfig and ServletContext objects. These objects can provide access to information about the current servlet configuration and context.

To obtain the ServletConfig and ServletContext objects in a Spring bean, we must first implement the ServletContextAware and ServletConfigAware interfaces in the bean class. Then we can override the setServletContext() and setServletConfig() methods to obtain the ServletContext and ServletConfig objects, respectively.

Here's an example:

public class MyBean implements ServletContextAware, ServletConfigAware {

private ServletContext servletContext; private ServletConfig servletConfig;

@Override public void setServletContext(ServletContext servletContext) { this.servletContext = servletContext; }

@Override public void setServletConfig(ServletConfig servletConfig) { this.servletConfig = servletConfig; }

// ... rest of the class ...


Now that we have the ServletContext and ServletConfig objects in our bean, we can use them to access any configuration or context-related information we need.

Difference between a Bean Factory and an Application Context

In the Spring Framework, a Bean Factory and an Application Context are two key concepts with some fundamental differences.


is the basic interface for accessing a Spring container, which is responsible for creating, initializing, and managing the lifecycle of beans. It provides the configuration framework and implements the inversion of control principle.


is a centralized interface to provide configuration information to an application. It extends


and adds support for internationalization, resource loading, event propagation, and automatic bean post-processing.

In summary,


is a simple container for managing beans, while


is an advanced container with more features for enterprise-level applications.

Support for I18N and Localization in Spring MVC

Internationalization (I18N) and Localization are widely used in web applications to provide support for multiple languages and regions. Spring MVC provides built-in support for I18N and Localization.

To enable I18N and Localization support, Spring MVC provides a LocaleResolver interface which helps in resolving the locale of the user. The framework also comes with a few implementations of the LocaleResolver interface.

Spring MVC makes use of ResourceBundles to store message properties files. This enables the application to access translated messages for different languages, based on the locale provided by the LocaleResolver.

To use message properties files in Spring MVC, the application can create a message source bean that is responsible for accessing the message properties files and returning the translated message.

Overall, Spring MVC provides a robust framework for supporting I18N and Localization in web applications, making it easier for developers to create applications that can cater to users from different languages and regions.


MultipartResolver is an interface in Spring MVC that handles HTTP requests with 'multipart/form-data' content type, which is typically used for file uploads. It resolves the multipart form data and provides access to individual form fields and uploaded files. The implementation of this interface can be configured based on the requirements of the application.

Using Tomcat JNDI Datasource in a Spring Application

In order to use Tomcat JNDI DataSource in a Spring Application, you can follow the below steps:

1. Add the Tomcat JDBC Dependency to your pom.xml file:


2. Configure the JNDI datasource in Tomcat's context.xml file:

    <Resource name="jdbc/TestDB" auth="Container" type="javax.sql.DataSource"
                   username="root" password="password" driverClassName="com.mysql.jdbc.Driver"
                   url="jdbc:mysql://localhost:3306/testdb" maxActive="100" maxIdle="20"

3. In your Spring ApplicationContext you can retrieve the JNDI DataSource as shown below:

<jee:jndi-lookup id="myDataSource" jndi-name="jdbc/TestDB" />

4. Inject the DataSource in your Spring Beans using the following code:

<bean id="myDAO" class="com.example.MyDAO">
    <property name="dataSource" ref="myDataSource"/>

With these steps, your Spring application can use the Tomcat JNDI DataSource for database connectivity.

Checkbox Input Selection State After Validation Errors

Assuming the checkbox input was initially unchecked, if the user checks the box and receives validation errors in other fields, but then unchecks the checkbox, the selection state of the checkbox input will be unchecked. The validation errors in other fields will not affect the state of the checkbox input.

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