What Problems Did I Solve When Migrating Spring boot to 3.0.0

4 min readDec 3, 2022

screenshot from https://spring.io/projects/spring-boot

In this Story, I will show you what I have done for migrating the Spring Boot from 2.7.6 to 3.0 in my Event Sourcing P.O.C Repository.
(see also how to implement observability for spring boot 3)

For a brief introduction, my project is

A multi-module Gradle Project (gradle-wrapper 7.2)
Using Java 17
A server Application integrates with Kafka
Using H2 as an in-memory DB

the following is my original build.gradle file

plugins {
    id 'org.springframework.boot' version '2.7.6' apply false
    id 'io.spring.dependency-management' version '1.1.0'
    id 'java'
}

subprojects {

    group = 'org.example'
    version = '0.0.1-SNAPSHOT'
    sourceCompatibility = '17'

    apply plugin: 'java'
    apply plugin: 'io.spring.dependency-management'
    apply plugin: 'java-library'

    repositories {
        mavenCentral()
    }

    dependencyManagement {
        imports {
            mavenBom(SpringBootPlugin.BOM_COORDINATES)
        }
    }

    dependencies {
        implementation 'org.springdoc:springdoc-openapi-ui:1.6.13'
        testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
        testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
        runtimeOnly 'com.h2database:h2'

        compileOnly 'org.projectlombok:lombok:1.18.20'
        annotationProcessor 'org.projectlombok:lombok:1.18.20'
    }
    test {
        useJUnitPlatform()
    }
}

Migration step

1. update the gradle wrapper version

First, when I modify the ‘org.springframework.boot’ version to 3.0.0, and try to reload the project in my IDE(Intellij), I encounter the first problem:

Root cause: PermittedSubclasses requires ASM9

org.gradle.api.ProjectConfigurationException: A problem occurred configuring root project 'event-sourcing-order-poc'.
Caused by: org.gradle.internal.UncheckedException: java.util.concurrent.ExecutionException: org.gradle.api.GradleException: Failed to create Jar file /Users/myname/.gradle/caches/jars-9/4d6cded054513435538f8c1f816f4acb/spring-core-6.0.2.jar.
 ... 
Caused by: java.util.concurrent.ExecutionException: org.gradle.api.GradleException: Failed to create Jar file /Users/myname/.gradle/caches/jars-9/4d6cded054513435538f8c1f816f4acb/spring-core-6.0.2.jar.
 ... 156 more
Caused by: org.gradle.api.GradleException: Failed to create Jar file /Users/myname/.gradle/caches/jars-9/4d6cded054513435538f8c1f816f4acb/spring-core-6.0.2.jar.
 ... 3 more
Caused by: java.lang.UnsupportedOperationException: PermittedSubclasses requires ASM9

There is no useful information when just google with the “PermittedSubclasses requires ASM9”. But we can see that the problem is absolutely related to the Gradle. so I try to update the gradle wrapper version in my project( from 7.2 to 7.6). And it turns out to solve this issue.

2. replace the import package from “javax” to “jakarta”

This change is noted in the document in the [Official Migration Guide](https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-3.0-Migration-Guide), so it is not a big problem.

But after replacing the package name, I encounter a warning message when trying to run the application:

jakarta.validation.NoProviderFoundException: 
Unable to create a Configuration, because no Jakarta Bean Validation provider could be found. 
Add a provider like Hibernate Validator (RI) to your classpath.

So we add the following dependency to the project and solve the issue.[(ref StackOverflow)](https://stackoverflow.com/questions/36329001/unable-to-create-a-configuration-because-no-bean-validation-provider-could-be-f)

implementation 'org.springframework.boot:spring-boot-starter-validation'

3. change the deprecated Method in CompletableFuture

There is a deprecated method called, “addCallback()” in the following Kafka event producer class. the method is officially removed after this change. so I have to find another way to implement the logic.

return kafkaTemplate.executeInTransaction(operations -> {
            final String key = order.id();
            operations
                    .send(ORDER_TOPIC, key, order)
                    .addCallback(this::onSuccess, this::onFailure);
            return true;
        });
...
private void onSuccess(final SendResult<String, OrderEvent> result) {...}
private void onFailure(final Throwable t) {
        log.warn("Unable to write Order to topic {}.", ORDER_TOPIC, t);
    }

Here, I replaced it with two functions, “thenAccept” and “exceptionally” to make the same logic. then modify the return type of “onFailure()” method:

return kafkaTemplate.executeInTransaction(operations -> {
            final String key = order.id();
            operations
                    .send(ORDER_TOPIC, key, order)
                    .thenAccept(this::onSuccess)
                    .exceptionally(this::onFailure);
            return true;
        });
...
private void onSuccess(final SendResult<String, OrderEvent> result) {...}
private Void onFailure(final Throwable t) {
        log.warn("Unable to write Order to topic {}.", ORDER_TOPIC, t);
        return null;
    }

4. Use new dependency for swagger UI

Finally, I can build and run my project, but the server returns a not-found for the swagger UI URL. I go to the official website of the springdoc and found that it says:

so I change the dependency from

dependencies {
    implementation 'org.springdoc:springdoc-openapi-ui:1.6.13'
}

dependencies {
    implementation 'org.springdoc:springdoc-openapi-starter-webmvc-ui:2.0.0'
}

then the swagger UI is working fine again.

Summary

Here we just have done the very first step, migrating my project to using the 3.0.0 version. looking forward to integrating all the exciting features into my project next time. if you want to see the code change in detail, you can refer to this Pull Request in my P.O.C GitHub repository: https://github.com/NoahHsu/event-sourcing-order-poc/pull/16.

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Reference

release note: https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-3.0-Release-Notes
migration guide: https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-3.0-Migration-Guide
springdoc official doc: https://springdoc.org/v2/
StackOverflow about jakarta.validation: https://stackoverflow.com/questions/36329001/unable-to-create-a-configuration-because-no-bean-validation-provider-could-be-f