spring-boot-maven-plugin doesn't work with Java 22

[krzyk]

Steps to reproduce:

1. Go to https://start.spring.io/
2. Generate project with Maven and Java 21 (don't change anything else)
3. Download, unzip
4. Change <java.version>21</java.version> to <java.version>22</java.version>
5. Execute mvn clean verify

Results with:

[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:3.2.3:repackage (repackage) on project demo: Execution repackage of goal org.springframework.boot:spring-boot-maven-plugin:3.2.3:repackage failed: Unsupported class file major version 66 -> [Help 1]

This is because spring-boot-maven-plugin:3.2.3 uses old ASM version 9.5. Easily to see using mvn dependency:resolve-plugins:

...
[INFO]       org.ow2.asm:asm:jar:9.5
[INFO]       org.ow2.asm:asm-commons:jar:9.5
[INFO]       org.ow2.asm:asm-tree:jar:9.5
...

[mhalbritter]

Can reproduce this. Here's the stacktrace:

org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:3.2.3:repackage (repackage) on project java22: Execution repackage of goal org.springframework.boot:spring-boot-maven-plugin:3.2.3:repackage failed: Unsupported class file major version 66
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:333)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:316)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:212)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:174)
    at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:75)
    at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:162)
    at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:159)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:73)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:53)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:118)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:261)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:906)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:283)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:206)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:580)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:283)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:226)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:407)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:348)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:580)
    at org.apache.maven.wrapper.BootstrapMainStarter.start (BootstrapMainStarter.java:52)
    at org.apache.maven.wrapper.WrapperExecutor.execute (WrapperExecutor.java:161)
    at org.apache.maven.wrapper.MavenWrapperMain.main (MavenWrapperMain.java:73)
Caused by: org.apache.maven.plugin.PluginExecutionException: Execution repackage of goal org.springframework.boot:spring-boot-maven-plugin:3.2.3:repackage failed: Unsupported class file major version 66
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:133)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:328)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:316)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:212)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:174)
    at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:75)
    at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:162)
    at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:159)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:73)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:53)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:118)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:261)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:906)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:283)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:206)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:580)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:283)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:226)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:407)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:348)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:580)
    at org.apache.maven.wrapper.BootstrapMainStarter.start (BootstrapMainStarter.java:52)
    at org.apache.maven.wrapper.WrapperExecutor.execute (WrapperExecutor.java:161)
    at org.apache.maven.wrapper.MavenWrapperMain.main (MavenWrapperMain.java:73)
Caused by: java.lang.IllegalArgumentException: Unsupported class file major version 66
    at org.springframework.asm.ClassReader.<init> (ClassReader.java:199)
    at org.springframework.asm.ClassReader.<init> (ClassReader.java:180)
    at org.springframework.asm.ClassReader.<init> (ClassReader.java:166)
    at org.springframework.asm.ClassReader.<init> (ClassReader.java:287)
    at org.springframework.boot.loader.tools.MainClassFinder.createClassDescriptor (MainClassFinder.java:254)
    at org.springframework.boot.loader.tools.MainClassFinder.doWithMainClasses (MainClassFinder.java:216)
    at org.springframework.boot.loader.tools.MainClassFinder.findSingleMainClass (MainClassFinder.java:197)
    at org.springframework.boot.loader.tools.Packager.findMainMethod (Packager.java:351)
    at org.springframework.boot.loader.tools.Packager.findMainMethodWithTimeoutWarning (Packager.java:340)
    at org.springframework.boot.loader.tools.Packager.getMainClass (Packager.java:335)
    at org.springframework.boot.loader.tools.Packager.addMainAndStartAttributes (Packager.java:315)
    at org.springframework.boot.loader.tools.Packager.buildManifest (Packager.java:300)
    at org.springframework.boot.loader.tools.Packager.write (Packager.java:211)
    at org.springframework.boot.loader.tools.Packager.write (Packager.java:204)
    at org.springframework.boot.loader.tools.Repackager.repackage (Repackager.java:151)
    at org.springframework.boot.loader.tools.Repackager.repackage (Repackager.java:138)
    at org.springframework.boot.maven.RepackageMojo.repackage (RepackageMojo.java:227)
    at org.springframework.boot.maven.RepackageMojo.execute (RepackageMojo.java:217)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:328)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:316)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:212)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:174)
    at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:75)
    at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:162)
    at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:159)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:73)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:53)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:118)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:261)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:173)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:101)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:906)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:283)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:206)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:580)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:283)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:226)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:407)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:348)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:580)
    at org.apache.maven.wrapper.BootstrapMainStarter.start (BootstrapMainStarter.java:52)
    at org.apache.maven.wrapper.WrapperExecutor.execute (WrapperExecutor.java:161)
    at org.apache.maven.wrapper.MavenWrapperMain.main (MavenWrapperMain.java:73)

[mhalbritter]

Same with 3.3.0-SNAPSHOT.

[mhalbritter]

The maven plugin uses spring-core:6.0.10:

[INFO]    org.springframework.boot:spring-boot-maven-plugin:maven-plugin:3.3.0-SNAPSHOT:runtime
...
[INFO]       org.springframework:spring-core:jar:6.0.10

but otherwise a current version of the framework dependencies:

[INFO]       org.springframework:spring-context:jar:6.1.5-SNAPSHOT
[INFO]       org.springframework:spring-aop:jar:6.1.5-SNAPSHOT
[INFO]       org.springframework:spring-beans:jar:6.1.5-SNAPSHOT
[INFO]       org.springframework:spring-expression:jar:6.1.5-SNAPSHOT

Is that because of the dependencies on spring-boot-buildpack-platform and spring-boot-loader-tools, which both have 6.0.10 in their POM?

[wilkinsona]

Oh dear. Those mixed versions are bad. We had to downgrade to Framework 6.0.x in the build plugin-related projects to work around this Gradle bug that's been fixed in Gradle 7.6.4.

As a first step, I think we should try to configure the Maven plugin to consistently use 6.1.x. As a second step, and probably in a separate issue, we'll have to figure out what to do about Gradle. I'm not sure how we can both support Java 22 and Gradle versions < 7.6.4. We could raise the minimum supported version of Gradle for Boot 3.3 but that'd still leave us with a problem in Boot 3.2.x.

[wilkinsona]

Gradle does not yet support Java 22. 8.7, currently in its RC phase will support using a Java 22 toolchain but won't support running Gradle itself on Java 22. That buys us some time on the Gradle side of things.