Today, in the fast-paced digital world, speed and agility are pivotal for successful software development. For Java developers, long winded set up processes delay the progress. Typically, conventional Java application development needs complex set up and consumes time. But fret not, Spring Boot is a game changer.
The flexible framework facilitates building web applications, application programming interfaces, and services. Top of all, developers can focus on writing business logic instead of the tedious setup. In this article, we shall look into the Spring Boot framework, its upsides, and why it is considered an excellent choice for developers wanting to improve productivity and efficiency.
An open-source Java-based framework for creating stand-alone, production-grade Spring-based applications with minimal configuration, Spring Boot forms part of a larger Spring Framework ecosystem. Further, it simplifies the development process through automatic configurations and tools.
Rod Jonhson, Juergen Hoeller, and Yann Caroff created the open-source Spring framework in 2003 to facilitate Java server-side development and enable development teams to produce applications more rapidly.
Even though it increased the easiness and reliability of the application, it had its fair share of problems, out of which 3 fundamental issues where:
An issue filed on the Spring GitHub repo title in 2012, “Improved support for ‘containerless’ web application architectures” in which the author, Mike Youngstrom had made a call to simplify Spring’s web application architecture.
Mr. Phil Webb was a member of the Spring team. On August 6, 2013, Phil wrote, that instead of resolving this as part of the core Spring Framework, they wanted to start a new project called Spring Boot that resolves all issues. Phil Webb was a member of the team that created the Spring Boot.
Typically, the Spring Framework’s architecture focuses on dependency injection and aspect-oriented programming, empowering developers to create modular and loosely coupled applications.
At the heart of spring architecture is the Inversion of Control (IoC) container, which handles object lifecycles and wiring. Also, it supports various Spring Data for database integration and modules like Spring MVC for web development, ensuring flexibility and scalability.
Dependency Injection (DI) is a design pattern that reduces the coupling between the application components and keeps the application more modular and easier to maintain.
Moreover, it helps manage how objects obtain their dependencies, for example, services or objects for their functioning.
The Spring framework supports an Inversion of Control (IoC) container that manages JavaBeans, and the ApplicationContext. Also, it provides a centralized view of the entire application’s configuration.
Aspect-Oriented Programming (AOP) helps developers modularize cross-cutting concerns, for example, logging, security, and transaction management, and apply them to several components of an application.
As a result, it offers code modularity and reusability. Moreover, the Spring framework has an AOP framework that handles cross-cutting concerns in the application.
The Spring framework architecture relies on separation of concerns, modularity, and flexibility as it uses a set of tools to build powerful and scalable applications.
The Spring framework covers several modules. It is classified into four major areas:
The Core Container deals with the fundamental functionality of the Spring framework. Also, it includes the Inversion of Control (IoC) container and the ApplicationContext. The following modules are related to Core Container:
Spring Data features automatic CRUD (Create, Read, Update, Delete) operations, query generation, provides support for pagination. Also, for sorting, along with Spring’s transaction management integration, and many more.
Apart from these, Spring Data supports common data access patterns like data access objects (DAO) and repositories.
The Data Access/Integration offers support for integrating with databases and other data sources. It includes the following modules:
This module provides JDBC abstraction layer that reduces the boilerplate code required to work with JDBC. Also, it supports transaction management, facilitating developers handle database transactions declaratively with the help of transaction management.
This module assists in integration with Object-Relational Mapping (ORM) frameworks. For example, Hibernate and JPA. Spring ORM has higher-level abstraction layer on top of ORM frameworks. As a result, it helps developers to write less boilerplate code. Further, it effortlessly integrates ORM technologies with other Spring features (transaction management and caching).
This module provides a unified abstraction and encapsulation layer for popular O-X mapping frameworks (such as Castor, JAXB, XMLBeans, and XStream).
Additionally, it streamlines the process of marshalling or unmarshalling data between Java objects and XML representations.
This module provides a high-level, easy-to-use API that connects message brokers, send messages, and process them asynchronously. It abstracts the complexities of working with the JMS API, making it more developer-friendly.
It uses @jmsTemplate for message production and synchronous message reception and @JmsListener to create message listeners in Spring-managed beans.
Spring JMS promotes loose coupling by handling how objects obtain their JMS dependencies and seamlessly integrates with various message brokers (e.g., Apache ActiveMQ, RabbitMQ).
This module provides support for declarative transaction management in Spring applications. Furthermore, it supports several transaction propagation, and isolation levels, allowing developers to manage transactions at various levels of granularity.
Also, spring transaction takes care of different transaction management approaches; for example, a JTA transaction manager or a JDBC transaction manager.
Spring Web focuses on web-related features and integration for building web applications.
Spring Web provides functionality to handle multipart file uploads. This is essential for processing files (e.g., images, documents) submitted via web forms.
When your web application starts, Spring initializes its Inversion of Control (IoC) container using servlet listeners. These listeners ensure that Spring’s beans are ready for use and are properly wired together, even in a web context.
The two distinct phases in Portlet requests include:
Spring Web-Portlet preserves this separation, allowing clean handling of state modification and rendering.
AOP is a programming paradigm that helps modularizing the cross-cutting concerns (for example security, logging, and transaction management) distinctively from the core application logic.
In Spring, these modules enable you to define aspects (cross-cutting concerns). Also, apply them to specific parts of your code (e.g., methods).
You can set up Spring AOP using XML or annotations.
Instrumentation involves modifying or enhancing classes at runtime. In Spring, the Instrumentation module provides support for class instrumentation and `classloader implementations`. It allows you to manipulate classes dynamically, for example, to add monitoring or profiling capabilities.
Also, instrumentation is often used for performance analysis, debugging, and other runtime modifications.
Instrumentation typically involves modifying or observing code execution at runtime, and Spring Actuator provides a way to observe and manage your Spring Boot application.
Spring Actuator is a module that supports production-ready features and also monitors and manages Spring Boot applications. Firther, it exposes various endpoints (accessible via HTTP or JMX) that allow you to gather runtime information about your application.
Examples of endpoints provided by Spring Actuator include /health, /metrics, /info, and /env. These endpoints help you monitor application health, performance metrics, and other operational aspects.
Spring Test simplifies testing Spring components, ensuring consistent context loading and providing mock objects for effective unit testing. Further, spring test supports both unit testing and integration testing of Spring components using JUnit or TestNG.
Spring Test ensures consistent loading and caching of Spring ApplicationContexts during tests and provides mock objects that allow you to test your code in isolation.
Spring Boot projects have a streamlined structure to keep things organized and efficient. At the top, you have the src directory, housing your main application code and resources.
Within src/main, you will find java for your Java files, resources for configuration files like application.properties, and webapp for web resources.
The src/test directory mirrors this structure for your test code. The root directory includes files like pom.xml or build.gradle for managing dependencies.
This clear, hierarchical layout makes it easy to navigate and manage your project.
pom.xml or build.gradle: It is the build configuration file for Maven or Gradle. It features plugins, project dependencies, and other build-related configurations.
src: is the source directory that features the application code and resources.
Contains the main application code.
com.example.projectname: is the base package for your application and features a hierarchical structure.
Application.java: The key entry point of the Spring Boot application, annotated with @SpringBootApplication.
controller: includes the REST controllers for handling HTTP requests.
service: features the service layer that implements the business logic.
repository: includes the repository interfaces for data access, and often extends to Spring Data JPA repositories.
model: features the domain models and entities that represent the data.
config: Contains security configurations, database configurations, and so on.
application.properties or application.yml: is the key configuration file for the Spring Boot application.
static: includes static files like HTML, JavaScript, CSS, and images.
templates: feaures server-side templates ( For example, FreeMarker, Thymeleaf) for rendering views.
public: is an alternative location for static files, that are used for public resources.
META-INF/resources: is another alternative location for static files.
Includes test classes.
com.example.projectname: is the base package for test classes, which often mirrors the structure of src/main/java.
Test classes for controllers, repositories, services, and other components.
ApplicationTests.java: is the major test entry point, annotated with @SpringBootTest.
Includes configuration files and test data or any test-specific resources.
target or build: is the output directory for the compiled code which is generated by Maven or Gradle.
Logs: this is the optional directory used for storing application logs.
In a Spring Boot application, the main class acts as the application entry point. Usually, this class is annotated with @SpringBootApplication. Also, it is a convenient annotation that can combine other annotations.
The @SpringBootApplication annotation features three important annotations:
When you run the main method, several things happen:
Many of the complexities and challenges inherent in the traditional Spring Framework gets addressed by Spring Boot. Also, it follows convention over configuration, provides auto-configuration, and integrates with various technologies effortlessly.
Spring Boot features a robust, developer-friendly platform to speed up web development and offers easy maintenance. Further, the streamlined configuration and production-ready features help developers focus on writing code. Therefore, it further assists in the rapid delivery of products.
At ThinkPalm, we build scalable and cloud-ready applications, and help our clients in the digital transformation journey, improving time-to market and thereby enhancing business growth.
Pavan Sunny Thomas is a Java Full Stack Developer with expertise in developing and maintaining Java-based web applications using Spring Boot, Hibernate, Angular, and other technologies. He is passionate about web development and enjoys learning new skills and tools. Also, an avid blogger, Pavan shares his insights and tips on web development and showcases his portfolio of projects.
