What does this ObjectWeb error mean: "Unsupported class file major version 56" and how do I fix it?

Question

(Editors note: This is objectweb, not the JVM complaining. Be very sure before knee-jerk closing as duplicate)

---

I'm sort of reviving a project that was left in a broken state when I try to run the tests I get this error:

Execution default-test of goal org.apache.maven.plugins:maven-surefire-plugin:2.22.0:test failed: Unsupported class file major version 56 

What does that mean? Any ideas how to fix it?

The Maven project includes:

    <pluginManagement>
        <plugins>
            <plugin> 
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.22.0</version>
            </plugin>
        </plugins>
    </pluginManagement>

but commenting out that plug in makes no difference.

The full backtrace looks like this:

> mvn test -e
[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[INFO]
[INFO] --------------------< com.example:projectxserver >--------------------
[INFO] Building projectxserver 1.0.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[WARNING] The artifact org.hibernate:hibernate-validator:jar:6.0.17.Final has been relocated to org.hibernate.validator:hibernate-validator:jar:6.0.17.Final
[INFO]
[INFO] --- maven-resources-plugin:3.1.0:resources (default-resources) @ projectxserver ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] Copying 15 resources
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ projectxserver ---
[WARNING] ***********************************************************************************************************************************************************************
[WARNING] * Required filename-based automodules detected: [javax.servlet-api-4.0.1.jar, javax.inject-1.jar]. Please don't publish this project to a public artifact repository! *
[WARNING] ***********************************************************************************************************************************************************************
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:3.1.0:testResources (default-testResources) @ projectxserver ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ projectxserver ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.22.0:test (default-test) @ projectxserver ---
[INFO] Surefire report directory: C:\Users\pupeno\Documents\projectx\code\projectxserver\target\surefire-reports
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  5.463 s
[INFO] Finished at: 2019-09-24T18:10:19+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.22.0:test (default-test) on project projectxserver: Execution default-test of goal org.apache.maven.plugins:maven-surefire-plugin:2.22.0:test failed: Unsupported class file major version 56 -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.22.0:test (default-test) on project projectxserver: Execution default-test of goal org.apache.maven.plugins:maven-surefire-plugin:2.22.0:test failed: Unsupported class file major version 56
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:215)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:288)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:192)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:567)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
Caused by: org.apache.maven.plugin.PluginExecutionException: Execution default-test of goal org.apache.maven.plugins:maven-surefire-plugin:2.22.0:test failed: Unsupported class file major version 56
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:148)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:288)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:192)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:567)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
Caused by: java.lang.IllegalArgumentException: Unsupported class file major version 56
    at org.objectweb.asm.ClassReader.<init> (ClassReader.java:166)
    at org.objectweb.asm.ClassReader.<init> (ClassReader.java:148)
    at org.objectweb.asm.ClassReader.<init> (ClassReader.java:136)
    at org.objectweb.asm.ClassReader.<init> (ClassReader.java:237)
    at org.codehaus.plexus.languages.java.jpms.AsmModuleInfoParser.parse (AsmModuleInfoParser.java:115)
    at org.codehaus.plexus.languages.java.jpms.AsmModuleInfoParser.getModuleDescriptor (AsmModuleInfoParser.java:60)
    at org.codehaus.plexus.languages.java.jpms.LocationManager.resolvePaths (LocationManager.java:91)
    at org.apache.maven.plugin.surefire.AbstractSurefireMojo.newStartupConfigForModularClasspath (AbstractSurefireMojo.java:1810)
    at org.apache.maven.plugin.surefire.AbstractSurefireMojo.createStartupConfiguration (AbstractSurefireMojo.java:1753)
    at org.apache.maven.plugin.surefire.AbstractSurefireMojo.createForkStarter (AbstractSurefireMojo.java:2103)
    at org.apache.maven.plugin.surefire.AbstractSurefireMojo.executeProvider (AbstractSurefireMojo.java:1191)
    at org.apache.maven.plugin.surefire.AbstractSurefireMojo.executeAfterPreconditionsChecked (AbstractSurefireMojo.java:1022)
    at org.apache.maven.plugin.surefire.AbstractSurefireMojo.execute (AbstractSurefireMojo.java:868)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:288)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:192)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:567)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
[ERROR]
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginExecutionException

Update: I changed the Maven configuration source and target to be Java 11 and Java 10, like this:

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <source>10</source>
                <target>10</target>
            </configuration>
        </plugin>

and in both cases, the error changed to:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.22.0:test (default-test) on project projectxserver: Execution default-test of goal org.apache.maven.plugins:maven-surefire-plugin:2.22.0:test failed: Unsupported class file major version 55 -> [Help 1]

So, I guess that version isn't supported either.

Answer 1

You are using Java 12 (and compiling your code for it so the generated class files are only valid for Java 12 and newer).

The version of Objectweb which you are using under the covers does not support reading Java 12 classfiles (which is what version 56 corresponds to).

The easy fix is to reconfigure your build to compile for Java 11 or earlier depending on what version of Objectweb you need to use. Some experimentation may be necessary.

It may also be possible to update to latest version of objectweb if the issue has been fixed, but that may break other parts of your stack, so be certain to upgrade everything if you go this way.