Migrating Spring Boot 2.7.x to Spring Boot 3.x.x: A Comprehensive Guide

Introduction
Preparing for the Migration
Upgrading to Spring Boot 3.x.x
Updating Dependencies and Configurations
Handling Security Changes
Resolving Common Issues
Testing and Validation
Conclusion

Introduction

Spring Boot has been a cornerstone in building robust Java applications, offering a streamlined approach to development by minimizing boilerplate code and configurations. With the release of Spring Boot 3.x.x, developers are presented with enhanced features, improved performance, and better security mechanisms. Migrating from Spring Boot 2.7.x to 3.x.x is a significant step that can propel your application into a more efficient and secure future.

Importance of Migration

Enhanced Performance: Spring Boot 3.x.x introduces optimizations that make applications run faster and more efficiently.
Improved Security: Updated security frameworks and protocols ensure that applications are better protected against vulnerabilities.
Long-Term Support (LTS): Spring Boot 3.x.x offers extended support, ensuring that your application remains stable and secure over time.
Modern Features: Access to the latest features and integrations facilitates the development of modern, scalable applications.

Pros and Cons of Migrating

Pros	Cons
Improved performance	Potential compatibility issues
Enhanced security features	Learning curve for updated frameworks
Access to new functionalities	Time and resources required for migration
Long-term support and updates	Temporary instability during transition

When and Where to Use Spring Boot 3.x.x

Spring Boot 3.x.x is ideal for applications that require modern features, enhanced security, and long-term stability. It’s particularly beneficial for enterprise-level applications that need to stay updated with the latest technological advancements.

Preparing for the Migration

Before diving into the migration process, it’s crucial to assess the current state of your application and ensure that you’re ready for the transition.

Assessing Current Application

Codebase Analysis: Review your existing code to identify deprecated methods and configurations.
Dependency Inventory: List all dependencies to check their compatibility with Spring Boot 3.x.x.
Testing Frameworks: Ensure that your testing frameworks are compatible or have updates available.

Backup and Version Control

Backup Current State: Always back up your current application to prevent data loss.
Use Version Control Systems: Utilize Git or other version control systems to manage changes effectively.

Understanding Compatibility

Spring Boot 3.x.x requires Java 17 as the baseline version. Ensure that your development environment is updated accordingly.

Upgrading to Spring Boot 3.x.x

The upgrade process involves several steps, including updating configuration files, dependencies, and handling deprecated methods.

Updating pom.xml

Begin by updating the pom.xml file to reference Spring Boot 3.x.x.


&lt;parent&gt;
    &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
    &lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
    &lt;version&gt;3.0.0&lt;/version&gt;
    &lt;relativePath/&gt; &lt;!-- lookup parent from repository --&gt;
&lt;/parent&gt;

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

</parent>

Explanation:

Version Change: Update the <version> tag to 3.0.0 to migrate to Spring Boot 3.x.x.
Relative Path: Ensures that the parent is correctly referenced from the repository.

Updating Spring Security Version

Spring Boot 3.x.x comes with an upgraded Spring Security version.


&lt;dependency&gt;
    &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
    &lt;artifactId&gt;spring-boot-starter-security&lt;/artifactId&gt;
    &lt;version&gt;6.0.0&lt;/version&gt;
&lt;/dependency&gt;

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-security</artifactId>

</dependency>

Explanation:

Spring Security Upgrade: The security version is updated to 6.0.0 to align with Spring Boot 3.x.x.

Resolving Maven Wrapper Issues

Ensure that the Maven wrapper properties are compatible with the new Spring Boot version.


# .mvn/wrapper/maven-wrapper.properties
distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-wrapper/maven-wrapper-3.8.4.jar

# .mvn/wrapper/maven-wrapper.properties

distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-wrapper/maven-wrapper-3.8.4.jar

Explanation:

Maven Wrapper Update: Adjust the distributionUrl to use the compatible Maven wrapper version.

Updating Dependencies and Configurations

Migration to Spring Boot 3.x.x requires updating various dependencies and configurations to ensure compatibility.

Switching to Jakarta-based APIs

Spring Boot 3.x.x has migrated from Java EE (javax) to Jakarta EE (jakarta) namespaces.

Before:


import javax.servlet.*;

import javax.servlet.*;

After:


import jakarta.servlet.*;

import jakarta.servlet.*;

Explanation:

Namespace Change: Update import statements from javax to jakarta to align with Jakarta EE standards.

Adjusting Thymeleaf Extras

Update Thymeleaf Extras for Spring Security.


&lt;dependency&gt;
    &lt;groupId&gt;org.thymeleaf.extras&lt;/groupId&gt;
    &lt;artifactId&gt;thymeleaf-extras-springsecurity6&lt;/artifactId&gt;
    &lt;version&gt;3.0.4&lt;/version&gt;
&lt;/dependency&gt;

<groupId>org.thymeleaf.extras</groupId>

<artifactId>thymeleaf-extras-springsecurity6</artifactId>

</dependency>

Explanation:

Thymeleaf Extras Update: Use thymeleaf-extras-springsecurity6 for compatibility with Spring Security 6.x.

Modifying application.properties

Ensure that all properties are correctly configured for the new version.


spring.main.banner-mode=off
spring.datasource.url=jdbc:mysql://localhost:3306/blogdb
spring.datasource.username=root
spring.datasource.password=secret

spring.main.banner-mode=off

spring.datasource.url=jdbc:mysql://localhost:3306/blogdb

spring.datasource.username=root

spring.datasource.password=secret

Explanation:

Property Validation: Verify that all properties are accurate and compatible with Spring Boot 3.x.x requirements.

Handling Security Changes

Spring Boot 3.x.x introduces several changes in security configurations that need to be addressed during migration.

Deprecated Annotations

The @EnableGlobalMethodSecurity annotation is deprecated. Replace it with @EnableMethodSecurity.

Before:


@EnableGlobalMethodSecurity(prePostEnabled = true)
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
    // Configuration
}

@EnableGlobalMethodSecurity(prePostEnabled = true)

public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

// Configuration

}

After:


@EnableMethodSecurity
public class WebSecurityConfig {
    // Configuration
}

@EnableMethodSecurity

public class WebSecurityConfig {

// Configuration

}

Explanation:

Annotation Update: Switch to using @EnableMethodSecurity to activate method-level security.

Replacing antMatcher with requestMatcher

antMatcher methods are replaced by requestMatcher for enhanced security and performance.

Before:


@Override
protected void configure(HttpSecurity http) throws Exception {
    http
        .antMatcher("/admin/**")
        .authorizeRequests()
            .anyRequest().hasRole("ADMIN");
}

@Override

protected void configure(HttpSecurity http) throws Exception {

http

.antMatcher("/admin/**")

.authorizeRequests()

.anyRequest().hasRole("ADMIN");

}

After:


@Override
protected void configure(HttpSecurity http) throws Exception {
    http
        .requestMatcher(new AntPathRequestMatcher("/admin/**"))
        .authorizeRequests()
            .anyRequest().hasRole("ADMIN");
}

@Override

protected void configure(HttpSecurity http) throws Exception {

http

.requestMatcher(new AntPathRequestMatcher("/admin/**"))

.authorizeRequests()

.anyRequest().hasRole("ADMIN");

}

Explanation:

Method Replacement: Use requestMatcher instead of antMatcher to define URL patterns more securely and efficiently.

Resolving Common Issues

Migration may introduce several issues that need prompt resolution to ensure application stability.

Password Encoder Errors

Error Message:


The password encoder doesn't work. Unsatisfied dependencies.

The password encoder doesn't work. Unsatisfied dependencies.

Solution:

Ensure that a compatible password encoder is configured.


@Bean
public PasswordEncoder passwordEncoder() {
    return new BCryptPasswordEncoder();
}

@Bean

public PasswordEncoder passwordEncoder() {

return new BCryptPasswordEncoder();

}

Explanation:

Password Encoder Configuration: Define a PasswordEncoder bean using BCryptPasswordEncoder to handle password encoding securely.

Import Conflicts

Sometimes, import conflicts arise due to namespace changes.

Solution:

Use Jakarta imports and resolve conflicts.


import jakarta.servlet.Filter;

import jakarta.servlet.Filter;

Explanation:

Namespace Correction: Update import statements to use jakarta namespaces to eliminate conflicts.

Testing and Validation

After migrating, it’s essential to thoroughly test your application to ensure all functionalities work as expected.

Running the Application

Start your application and monitor the logs for any errors or warnings.


mvn spring-boot:run

mvn spring-boot:run

Explanation:

Startup Verification: Running the application helps identify any immediate issues introduced during migration.

Functional Testing

Verify all core functionalities such as login, logout, adding posts, updating profiles, etc., to ensure they operate seamlessly.

Security Testing

Ensure that all security configurations are effective and that unauthorized access is appropriately restricted.

Conclusion

Migrating from Spring Boot 2.7.x to 3.x.x is a strategic move that offers enhanced performance, improved security, and access to the latest features. While the migration process involves several steps, including updating configurations, dependencies, and handling deprecated methods, the long-term benefits make it a worthwhile endeavor. By following this comprehensive guide, developers can navigate the migration smoothly, ensuring their applications remain robust and secure.

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S12L01 – Spring Boot 2.7.x to Spring boot 3.x.x migrations

Migrating Spring Boot 2.7.x to Spring Boot 3.x.x: A Comprehensive Guide

Table of Contents

Introduction

Importance of Migration

Pros and Cons of Migrating

When and Where to Use Spring Boot 3.x.x

Preparing for the Migration

Assessing Current Application

Backup and Version Control

Understanding Compatibility

Upgrading to Spring Boot 3.x.x

Updating pom.xml

Updating Spring Security Version

Resolving Maven Wrapper Issues

Updating Dependencies and Configurations

Switching to Jakarta-based APIs

Adjusting Thymeleaf Extras

Modifying application.properties

Handling Security Changes

Deprecated Annotations

Replacing antMatcher with requestMatcher

Resolving Common Issues

Password Encoder Errors

Import Conflicts

Testing and Validation

Running the Application

Functional Testing

Security Testing

Conclusion