Be explicit with the spring-boot-maven-plugin version

[mjw99]

With the recent release of Spring Boot 3; this will default to that version and break the JDK{8,11} GitHub Actions since Spring Boot 3 is targeted for JDK 17 bytecode.

[johnmay]

Any thoughts on moving to JDK 17 required (other projects as well) and Spring/Jakarta EE? The jakarta EE renaming thing annoys me but I'm probably just being stubborn and think it's better to move with the times in this case.

[mjw99]

Hi John,

Internally, we are trying to run as many Java services with a 17 JDK in Docker containers. @sroughley also did migrate a Spring Boot REST service from 2.7 to 3 recently; IIRC the following guide was useful.

[mjw99]

As an aside, we have also found records to be very useful too.

[sroughley]

To confirm what @mjw99 mentioned the guide was the main starting point and covered the majority of issues. The move to the jakarta namespace was trivial in reality for us at least - simple find / replace for javax. to jakarata. "just worked".

The biggest gotcha was around the OpenAPI documentation, which we had to update to v2.0.x (currently 2.0.2), and update the dependencies to:

        <!-- For the Swagger / OpenAPI doc -->
        <dependency>
            <groupId>org.springdoc</groupId>
            <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
            <version>${openapi.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springdoc</groupId>
            <artifactId>springdoc-openapi-starter-common</artifactId>
            <version>${openapi.version}</version>
        </dependency>