We are updating Spring Boot from 3.3 to 3.4 and using the gradle plugin:
org.springframework.boot:spring-boot-gradle-plugin:3.4.1
We are having issues during the download of the libraries:
Namely the: jackson-core-2.18.2.jar
Error message: Unsupported class file major version 65
This looks like to be a Java 21 built library.
Though I've not read on the Spring Boot 3.4 Release Notes that an upgrade is needed to Java 21 from Java 17. 3.3 working fine, and I read in an article, that 3.4 keeps the baseline of Java 17.
Can you tell me, please, what is the standpoint regarding this? Will there be a replacement for the Java 21 libraries to Java 17? Are we forced now to upgrade to Java 21? Are there any workaround?
Comment From: snicoll
Unfortunately, "we're having issues" is not very descriptive.
Spring Boot 3.4 does not require Java 21 and Jackson did not move either. At this point, I don't know what problem you're facing is, or how it would be related to Spring Boot. If you want support, please attach a sample application we can run ourselves to reproduce the problem you've attempted to describe.
Comment From: wilkinsona
Perhaps you're using an old and unsupported version of Gradle that doesn't handle multi-release jars properly. If you're using Gradle 7.x, it must be 7.6.4 or later. If you're using Gradle 8.x, it must be 8.4 or later.
Comment From: adnsimona
Thanks @wilkinsona . Indeed we were using 7.6, and after upgrading to 7.6.4, the issue went away.