Upgrading to Spring Boot 3.x introduces significant changes, including the migration from Spring Framework 5.x to 6.x and the transition from Java EE to Jakarta EE namespaces. These changes can lead to runtime issues like java.lang.NoSuchMethodError, especially when methods such as Link.of() are invoked but not found at runtime. This article explores the causes of this error and provides practical solutions.
1. Understanding the NoSuchMethodError
The java.lang.NoSuchMethodError occurs when the JVM attempts to call a method that was available at compile-time but is missing at runtime. This often results from version mismatches between compiled classes and the libraries present during execution. In the context of Spring Boot 3.x, such errors frequently arise due to outdated dependencies that are incompatible with the latest Spring Framework 6.x.
2. Common Causes in Spring Boot 3.x
1. Outdated Dependencies
Dependencies compiled against older versions of Spring may reference methods that have been altered or removed in newer versions. For instance, spring-security-oauth2:jar:2.5.1.RELEASE is incompatible with Spring Framework 6 and Spring Boot 3, leading to NoSuchMethodError exceptions
2. Partial Compilation
If only parts of your application are recompiled after a dependency update, some classes may still reference outdated method signatures, causing runtime errors
3. Transitive Dependencies
Indirect dependencies might bring in incompatible versions of libraries. For example, spring-boot-starter-test previously pulled in android-json, which conflicted with org.json due to differing method implementations.
3. Diagnosing the Issue
To identify the root cause:
- Examine the Stack Trace: Look for the specific class and method causing the error.
- Check Dependency Versions: Use tools like
mvn dependency:treeorgradle dependenciesto inspect the versions of your project’s dependencies. - Identify Conflicting Libraries: Look for libraries that might be bringing in older versions of Spring or other dependencies.
4. Solutions
1. Align Dependency Versions
Ensure all dependencies are compatible with Spring Boot 3.x. Use Spring Boot’s dependency management to control versions
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>3.0.0</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
This approach helps maintain consistent versions across your project.
2. Rebuild the Project
Perform a clean build to ensure all classes are recompiled with the updated dependencies:
- Maven:
mvn clean install - Gradle:
./gradlew clean build
In IDEs like IntelliJ IDEA, use the “Rebuild Project” option to recompile all classes.
3. Exclude Problematic Transitive Dependencies
If a transitive dependency is causing conflicts, exclude it explicitly:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<exclusions>
<exclusion>
<groupId>com.vaadin.external.google</groupId>
<artifactId>android-json</artifactId>
</exclusion>
</exclusions>
</dependency>
This prevents the inclusion of incompatible libraries that might cause NoSuchMethodError exceptions.
4. Update Incompatible Libraries
Identify and update libraries that are not compatible with Spring Boot 3.x. For example, if using spring-security-oauth2, consider migrating to Spring Security 6.x, which is compatible with Spring Boot 3.x.
5. Example: Resolving NoSuchMethodError with Link.of()
Suppose you encounter the following error:
java.lang.NoSuchMethodError: 'org.springframework.hateoas.Link org.springframework.hateoas.Link.of(java.lang.String)'
This indicates that the Link.of() method is missing at runtime. To resolve this:
- Check the Version of
spring-hateoas: Ensure it’s compatible with Spring Boot 3.x. - Update the Dependency: In your
pom.xml:
<dependency>
<groupId>org.springframework.hateoas</groupId>
<artifactId>spring-hateoas</artifactId>
<version>2.0.0</version> <!-- Ensure this version is compatible with Spring Boot 3.x -->
</dependency>
- Rebuild the Project: Perform a clean build to recompile all classes.
6. Conclusion
Encountering NoSuchMethodError exceptions like those involving Link.of() in Spring Boot 3.x is often due to version mismatches or outdated dependencies. By aligning your project’s dependencies with Spring Boot 3.x requirements, performing clean builds, and excluding incompatible transitive dependencies, you can resolve these issues effectively.
For a comprehensive guide on migrating to Spring Boot 3.0, refer to the OpenRewrite migration recipe.
Further Resources
For more detailed guidance and tools to assist with migration and compatibility checks, explore the following resources:
- 📘 Spring Boot 3.0 Migration Guide (Official)
- 🔧 OpenRewrite Recipes for Spring Boot 3
- 📦 Spring Initializr for generating updated Spring Boot projects
- 🧪 Spring Boot Dependency Compatibility Checker
- 🛠️ Maven Dependency Tree Plugin for resolving version conflicts
