Prerequisites and Environment Setup
The most critical change in Spring Boot 3.x is the baseline Java version. While Spring Boot 2.7 supported Java 8, 11, and 17, Spring Boot 3.2 requires Java 17 or higher. Before modifying your codebase, ensure your development environment and CI/CD pipelines are configured to use JDK 17+. Attempting to run this migration on older JDKs will result in immediate compilation failures due to missing module descriptors and updated language features.
Additionally, you must update your IDE. Modern versions of Eclipse, IntelliJ IDEA, and VS Code have native support for Java 17+ and Jakarta EE namespaces. If you are using an older IDE version, upgrade it to avoid syntax highlighting errors and incorrect auto-completion suggestions for the new jakarta.* packages. This step is foundational; without a compatible runtime, no amount of configuration tweaking will allow the application to start.
Build Configuration Updates
The first technical hurdle is updating your build tool configuration, whether you use Maven or Gradle. You need to declare the new parent artifact and manage dependencies explicitly to avoid conflicts.
In pom.xml, change the parent reference:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>3.2.0</version>
<relativePath/>
</parent>Next, remove any explicit dependency management for Spring Boot starters if they were previously defined manually, allowing the parent POM to manage versions. For Jakarta Faces, you must include the spring-boot-starter-faces starter, which pulls in the necessary Tomcat and Mojarra implementations compatible with Jakarta EE 10 (Faces 4.0).
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-faces</artifactId>
</dependency>If you were using older versions of Mojarra or MyFaces directly, remove them to let the Spring Boot starter manage the lifecycle. Note that spring-boot-starter-faces defaults to Tomcat as the embedded server. If you prefer Jetty or Undertow, you may need to exclude the default Tomcat starter and add the specific server starter, ensuring the Faces implementation remains compatible.
Package Namespace Migration
The core challenge of this migration is the namespace shift from javax.faces and javax.el to jakarta.faces and jakarta.el. This affects every managed bean, facelet tag library, and configuration class. Manual replacement is error-prone and time-consuming for large projects.
While some developers suggest using tools like the Eclipse Transformer, direct source code transformation can be risky if not carefully validated against your specific custom components. A safer approach for many teams is to perform a systematic search-and-replace across the project root, followed by a rigorous compilation check. Ensure you replace:
javax.faces.context.FacesContextbecomesjakarta.faces.context.FacesContextjavax.annotation.PostConstructbecomesjakarta.annotation.PostConstructjavax.inject.Injectbecomesjakarta.inject.Inject
Be cautious with third-party libraries. If you rely on older UI component libraries (like PrimeFaces or OmniFaces), verify their release notes. Many major libraries have already released versions supporting Jakarta EE 10. Using outdated library versions will cause NoClassDefFoundError at runtime because they still reference the old javax namespaces.
Configuration and Bean Management
Spring Boot’s auto-configuration for Faces has changed slightly. In previous versions, you might have needed extensive XML configuration for faces-config.xml. With Spring Boot 3.x, the focus shifts toward annotation-driven configuration. Ensure your faces-config.xml (if used) updates its schema location to the Jakarta EE 10 namespace:
<faces-config xmlns="https://jakarta.ee/xml/ns/jakartaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/faces_4_0.xsd"
version="4.0">Furthermore, check your application.properties or yml files. Properties related to Facelets caching or resource loading may need review. The default behavior for static resources has been tightened for security. If you serve static JSF resources from src/main/resources/META-INF/resources, ensure these paths are correctly mapped. You may also need to adjust security configurations, particularly if you are using Spring Security alongside Faces, as the filter chain order might require rebalancing to ensure Faces requests are processed before security checks interfere with view rendering.
Testing and Validation
After compiling, run your unit tests first. Focus on integration tests that interact with the JSF lifecycle. You may encounter issues where mocked FacesContext objects fail because the underlying implementation classes have changed. Update your test mocks to use the jakarta variants.
For end-to-end validation, deploy the application locally and navigate through all major views. Pay attention to EL expressions. While the EL engine itself is largely compatible, any custom EL resolvers must now implement jakarta.el.ELResolver instead of javax.el.ELResolver. If you have custom resolvers, rewrite them to extend the new interface. This migration is a significant step toward future-proofing your application, aligning it with the broader Java ecosystem’s move to Jakarta EE.
Frequently Asked Questions
Can I use Java 8 for Spring Boot 3.2?
No, Spring Boot 3.2 strictly requires Java 17 or higher. Java 8 lacks the required module system support and language features needed for the framework to function. You must upgrade your JDK before attempting this migration.
Do I need to change my web.xml file?
If you are using Spring Boot’s embedded server, you likely do not have a web.xml. Spring Boot handles servlet initialization via annotations and auto-configuration. If you maintain a legacy web.xml, update the namespace references to Jakarta EE and consider migrating to annotation-based configuration.
How do I handle third-party JSF libraries?
You must upgrade third-party libraries to versions that support Jakarta EE 10. Most popular libraries like PrimeFaces have released Jakarta-compatible versions. Using old versions will cause classloading conflicts and runtime errors.
Will my existing Facelets work without changes?
The markup itself usually remains unchanged, but the backing beans and tag libraries must reference the new jakarta namespaces. Any custom tags implemented in Java must be recompiled against the Jakarta API.
Is there a risk of breaking EL expressions?
Standard EL expressions generally remain compatible. However, custom EL resolvers or functions relying on javax.el APIs must be rewritten to use jakarta.el. Test complex EL usage thoroughly after deployment.