Spring Boot 2.4.0 M1 Release Notes

Upgrading from Spring Boot 2.3

JUnit 5’s Vintage Engine Removed from `spring-boot-starter-test`

If you upgrade to Spring Boot 2.4 and see test compilation errors for JUnit classes such as org.junit.Test, this may be because JUnit 5’s vintage engine has been removed from spring-boot-starter-test. The vintage engine allows tests written with JUnit 4 to be run by JUnit 5. If you do not want to migrate your tests to JUnit 5 and wish to continue using JUnit 4, add a dependency on the Vintage Engine, as shown in the following example for Maven:

<dependency>
    <groupId>org.junit.vintage</groupId>
    <artifactId>junit-vintage-engine</artifactId>
    <scope>test</scope>
    <exclusions>
        <exclusion>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-core</artifactId>
        </exclusion>
    </exclusions>
</dependency>

If you are using Gradle, the equivalent configuration is shown in the following example:

testImplementation("org.junit.vintage:junit-vintage-engine") {
    exclude group: "org.hamcrest", module: "hamcrest-core"
}

Removal of Plugin Management for Flatten Maven Plugin

Spring Boot’s build no longer makes use of the Flatten Maven Plugin (flatten-maven-plugin) and plugin management for it has been removed. If you were relying on Spring Boot’s managed version, you should add your own plugin management.