Why Spring Boot

Introduction

The Spring Framework is a powerful framework for building enterprise Java applications, but it can be complex and challenging to work with. Common issues include the need for extensive configuration, managing dependencies, deployment complexities, and handling boilerplate code. Spring Boot was created to solve these problems, making it easier for developers to build, run, and maintain Spring applications.

Problems with Using Spring Framework and How Spring Boot Solves Them

Problem 1: Complexity in Configuration

Issue: Traditional Spring applications require a lot of configuration. This can include setting up beans, data sources, transaction management, and more. This complexity can slow down development and make it harder to manage the application.

Solution: Spring Boot uses autoconfiguration to handle most of these settings automatically. By including the right dependencies, Spring Boot can set up default configurations for you.

Example: Setting up a data source

Without Spring Boot:

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

@Configuration
public class DataSourceConfig {
    @Bean
    public DriverManagerDataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost:3306/mydb");
        dataSource.setUsername("user");
        dataSource.setPassword("password");
        return dataSource;
    }
}

With Spring Boot:

You simply add the necessary properties to application.properties and Spring Boot configures the data source automatically.

spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=user
spring.datasource.password=password

Problem 2: Dependency Management

Issue: Managing dependencies manually can be cumbersome and prone to errors. Developers need to ensure that all versions of libraries and frameworks are compatible, which can be time-consuming.

Solution: Spring Boot provides starter dependencies, which are pre-defined sets of dependencies for different types of applications. These starters handle the complexity of dependency management for you.

Example: Adding dependencies for a web application

Without Spring Boot:

You need to manually add and manage multiple dependencies.

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
</dependency>
<dependency>
    <groupId>javax.validation</groupId>
    <artifactId>validation-api</artifactId>
</dependency>
<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-core</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-logging-juli</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-el</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-websocket</artifactId>
</dependency>

With Spring Boot:

You use a starter dependency that includes everything you need.

Maven Dependency:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

Problem 3: Deployment Complexity

Issue: Traditional Spring applications typically require deployment to an external server like Tomcat or Jetty. This adds an extra layer of complexity and maintenance.

Solution: Spring Boot applications come with embedded servers, meaning they can run independently without needing an external server. This simplifies deployment and makes the application more portable.

Example: Running the application

Without Spring Boot:

1. Package the application as a WAR file.
2. Deploy the WAR file to an external server like Tomcat.

With Spring Boot:

You package the application as a JAR file with an embedded server and run it directly.

java -jar my-application.jar

Problem 4: Boilerplate Code

Issue: Spring applications often require a lot of boilerplate code to set up basic functionalities like connecting to databases, managing transactions, and configuring security.

Solution: Spring Boot reduces boilerplate code by providing built-in features and sensible defaults. This allows developers to focus more on writing business logic rather than repetitive setup code.

Example: Setting up a REST controller

Without Spring Boot:

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@Configuration
@ComponentScan
public class AppConfig {
}

@RestController
public class MyController {
    @RequestMapping(value = "/hello", method = RequestMethod.GET)
    public String hello() {
        return "Hello, World!";
    }
}

With Spring Boot:

Spring Boot handles configuration and scanning automatically.

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
public class MyApplication {
    public static void main(String[] args) {
        SpringApplication.run(MyApplication.class, args);
    }
}

@RestController
public class MyController {
    @GetMapping("/hello")
    public String hello() {
        return "Hello, World!";
    }
}

Problem 5: Environment-Specific Configuration

Issue: Managing different configurations for various environments (development, testing, production) can be complicated.

Solution: Spring Boot supports externalized configuration and profiles, making it easier to manage environment-specific settings.

Example: Using profiles for different environments

application.properties (default settings):

spring.datasource.url=jdbc:mysql://localhost:3306/devdb
spring.datasource.username=devuser
spring.datasource.password=devpassword

application-prod.properties (production settings):

spring.datasource.url=jdbc:mysql://localhost:3306/proddb
spring.datasource.username=produser
spring.datasource.password=prodpassword

Activate the profile by setting an environment variable:

java -jar my-application.jar --spring.profiles.active=prod

Conclusion

Spring Boot addresses the complexities of the traditional Spring Framework by simplifying configuration, dependency management, and deployment. It reduces boilerplate code and supports environment-specific configurations, enabling developers to build, run, and maintain Spring applications more efficiently. By leveraging Spring Boot, developers can focus on writing business logic and delivering features rather than dealing with setup and configuration challenges.