Incompatible with Gradle 7 (.1.1)

[ichaus-we]

Hi, we had to go from Gradle 6.7 to 7.1.1 because of JAVA 16 support. The problem is, that de.set.ecj fails to load.

Gradle error message:

What went wrong:
An exception occurred applying plugin request [id: 'de.set.ecj', version: '1.4.1']
 Failed to apply plugin 'de.set.ecj'.
    Could not create plugin of type 'EclipseCompilerPlugin'.
       Could not generate a decorated class for type EclipseCompilerPlugin.
          org/gradle/jvm/toolchain/JavaToolChain

build.gradle

*
 * This file was generated by the Gradle 'init' task.
 *
 * This generated file contains a sample Java library project to get you started.
 * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
 * User Manual available at https://docs.gradle.org/7.1.1/userguide/building_java_projects.html
 */

plugins {
        // Apply the java-library plugin for API and implementation separation.
        id 'java-library'
        id "de.set.ecj" version "1.4.1"
}

repositories {
        // Use Maven Central for resolving dependencies.
        mavenCentral()
}

dependencies {
        // Use JUnit Jupiter for testing.
        testImplementation 'org.junit.jupiter:junit-jupiter:5.7.1'

        // This dependency is exported to consumers, that is to say found on their compile classpath.
        api 'org.apache.commons:commons-math3:3.6.1'

        // This dependency is used internally, and not exposed to consumers on their own compile classpath.
        implementation 'com.google.guava:guava:30.1-jre'
}

tasks.named('test') {
        // Use JUnit Platform for unit tests.
        useJUnitPlatform()
}

ecj.toolVersion = '3.26.0'

Full Gradle output:

Working Directory: C:\Users\nn\AppData\Roaming\workspace_developer\test6\lib
Gradle user home: C:\Users\nn\.gradle
Gradle Distribution: Gradle wrapper from target build
Gradle Version: 7.1.1
Java Home: C:\Program Files\Java\jdk-16.0.1_openJDK
JVM Arguments: None
Program Arguments: --stacktrace
Build Scans Enabled: false
Offline Mode Enabled: false
Gradle Tasks: classes

FAILURE: Build failed with an exception.

* Where:
Build file 'C:\Users\nn\AppData\Roaming\workspace_developer\test6\lib\build.gradle' line: 12

* What went wrong:
An exception occurred applying plugin request [id: 'de.set.ecj', version: '1.4.1']
> Failed to apply plugin 'de.set.ecj'.
   > Could not create plugin of type 'EclipseCompilerPlugin'.
      > Could not generate a decorated class for type EclipseCompilerPlugin.
         > org/gradle/jvm/toolchain/JavaToolChain

* Try:
Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Exception is:
org.gradle.api.plugins.InvalidPluginException: An exception occurred applying plugin request [id: 'de.set.ecj', version: '1.4.1']
    at org.gradle.plugin.use.internal.DefaultPluginRequestApplicator.exceptionOccurred(DefaultPluginRequestApplicator.java:207)
    at org.gradle.plugin.use.internal.DefaultPluginRequestApplicator.applyPlugin(DefaultPluginRequestApplicator.java:189)
    at org.gradle.plugin.use.internal.DefaultPluginRequestApplicator.lambda$applyLegacyPlugins$3(DefaultPluginRequestApplicator.java:138)
    at org.gradle.plugin.use.internal.DefaultPluginRequestApplicator.applyLegacyPlugins(DefaultPluginRequestApplicator.java:138)
    at org.gradle.plugin.use.internal.DefaultPluginRequestApplicator.applyPlugins(DefaultPluginRequestApplicator.java:122)
    at org.gradle.configuration.DefaultScriptPluginFactory$ScriptPluginImpl.apply(DefaultScriptPluginFactory.java:117)
    at org.gradle.configuration.BuildOperationScriptPlugin$1.run(BuildOperationScriptPlugin.java:65)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:75)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:68)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:153)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:68)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:56)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.lambda$run$1(DefaultBuildOperationExecutor.java:74)
    at org.gradle.internal.operations.UnmanagedBuildOperationWrapper.runWithUnmanagedSupport(UnmanagedBuildOperationWrapper.java:45)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:74)
    at org.gradle.configuration.BuildOperationScriptPlugin.lambda$apply$0(BuildOperationScriptPlugin.java:62)
    at org.gradle.configuration.internal.DefaultUserCodeApplicationContext.apply(DefaultUserCodeApplicationContext.java:44)
    at org.gradle.configuration.BuildOperationScriptPlugin.apply(BuildOperationScriptPlugin.java:62)
    at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.lambda$applyToMutableState$0(DefaultProjectStateRegistry.java:280)
    at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.fromMutableState(DefaultProjectStateRegistry.java:307)
    at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.applyToMutableState(DefaultProjectStateRegistry.java:279)
    at org.gradle.configuration.project.BuildScriptProcessor.execute(BuildScriptProcessor.java:42)
    at org.gradle.configuration.project.BuildScriptProcessor.execute(BuildScriptProcessor.java:26)
    at org.gradle.configuration.project.ConfigureActionsProjectEvaluator.evaluate(ConfigureActionsProjectEvaluator.java:35)
    at org.gradle.configuration.project.LifecycleProjectEvaluator$EvaluateProject.lambda$run$0(LifecycleProjectEvaluator.java:100)
    at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.lambda$applyToMutableState$0(DefaultProjectStateRegistry.java:280)
    at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.lambda$withProjectLock$3(DefaultProjectStateRegistry.java:340)
    at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:213)
    at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.withProjectLock(DefaultProjectStateRegistry.java:340)
    at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.fromMutableState(DefaultProjectStateRegistry.java:321)
    at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.applyToMutableState(DefaultProjectStateRegistry.java:279)
    at org.gradle.configuration.project.LifecycleProjectEvaluator$EvaluateProject.run(LifecycleProjectEvaluator.java:91)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:75)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:68)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:153)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:68)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:56)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.lambda$run$1(DefaultBuildOperationExecutor.java:74)
    at org.gradle.internal.operations.UnmanagedBuildOperationWrapper.runWithUnmanagedSupport(UnmanagedBuildOperationWrapper.java:45)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:74)
    at org.gradle.configuration.project.LifecycleProjectEvaluator.evaluate(LifecycleProjectEvaluator.java:63)
    at org.gradle.api.internal.project.DefaultProject.evaluate(DefaultProject.java:741)
    at org.gradle.api.internal.project.DefaultProject.evaluate(DefaultProject.java:149)
    at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.ensureConfigured(DefaultProjectStateRegistry.java:253)
    at org.gradle.execution.TaskPathProjectEvaluator.configure(TaskPathProjectEvaluator.java:41)
    at org.gradle.execution.TaskPathProjectEvaluator.configureHierarchy(TaskPathProjectEvaluator.java:57)
    at org.gradle.configuration.DefaultProjectsPreparer.prepareProjects(DefaultProjectsPreparer.java:50)
    at org.gradle.configuration.BuildTreePreparingProjectsPreparer.prepareProjects(BuildTreePreparingProjectsPreparer.java:64)
    at org.gradle.configuration.BuildOperationFiringProjectsPreparer$ConfigureBuild.run(BuildOperationFiringProjectsPreparer.java:52)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:75)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:68)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:153)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:68)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:56)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.lambda$run$1(DefaultBuildOperationExecutor.java:74)
    at org.gradle.internal.operations.UnmanagedBuildOperationWrapper.runWithUnmanagedSupport(UnmanagedBuildOperationWrapper.java:45)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:74)
    at org.gradle.configuration.BuildOperationFiringProjectsPreparer.prepareProjects(BuildOperationFiringProjectsPreparer.java:40)
    at org.gradle.initialization.VintageBuildModelController.prepareProjects(VintageBuildModelController.java:85)
    at org.gradle.initialization.VintageBuildModelController.doBuildStages(VintageBuildModelController.java:69)
    at org.gradle.initialization.VintageBuildModelController.scheduleRequestedTasks(VintageBuildModelController.java:61)
    at org.gradle.internal.build.DefaultBuildLifecycleController.lambda$scheduleRequestedTasks$1(DefaultBuildLifecycleController.java:112)
    at org.gradle.internal.build.DefaultBuildLifecycleController.withModel(DefaultBuildLifecycleController.java:134)
    at org.gradle.internal.build.DefaultBuildLifecycleController.scheduleRequestedTasks(DefaultBuildLifecycleController.java:110)
    at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.lambda$fromBuildModel$2(DefaultBuildTreeLifecycleController.java:72)
    at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.lambda$doBuild$4(DefaultBuildTreeLifecycleController.java:105)
    at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:213)
    at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.doBuild(DefaultBuildTreeLifecycleController.java:99)
    at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.fromBuildModel(DefaultBuildTreeLifecycleController.java:70)
    at org.gradle.tooling.internal.provider.runner.BuildModelActionRunner.run(BuildModelActionRunner.java:52)
    at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
    at org.gradle.internal.buildtree.ProblemReportingBuildActionRunner.run(ProblemReportingBuildActionRunner.java:50)
    at org.gradle.launcher.exec.BuildOutcomeReportingBuildActionRunner.run(BuildOutcomeReportingBuildActionRunner.java:69)
    at org.gradle.tooling.internal.provider.FileSystemWatchingBuildActionRunner.run(FileSystemWatchingBuildActionRunner.java:90)
    at org.gradle.launcher.exec.BuildCompletionNotifyingBuildActionRunner.run(BuildCompletionNotifyingBuildActionRunner.java:41)
    at org.gradle.launcher.exec.RootBuildLifecycleBuildActionExecutor.lambda$execute$0(RootBuildLifecycleBuildActionExecutor.java:40)
    at org.gradle.composite.internal.DefaultRootBuildState.run(DefaultRootBuildState.java:128)
    at org.gradle.launcher.exec.RootBuildLifecycleBuildActionExecutor.execute(RootBuildLifecycleBuildActionExecutor.java:40)
    at org.gradle.internal.buildtree.DefaultBuildTreeContext.execute(DefaultBuildTreeContext.java:40)
    at org.gradle.launcher.exec.BuildTreeLifecycleBuildActionExecutor.lambda$execute$0(BuildTreeLifecycleBuildActionExecutor.java:40)
    at org.gradle.internal.buildtree.BuildTreeState.run(BuildTreeState.java:53)
    at org.gradle.launcher.exec.BuildTreeLifecycleBuildActionExecutor.execute(BuildTreeLifecycleBuildActionExecutor.java:40)
    at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor$3.call(RunAsBuildOperationBuildActionExecutor.java:61)
    at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor$3.call(RunAsBuildOperationBuildActionExecutor.java:57)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:200)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:195)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:75)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:68)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:153)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:68)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:62)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.lambda$call$2(DefaultBuildOperationExecutor.java:79)
    at org.gradle.internal.operations.UnmanagedBuildOperationWrapper.callWithUnmanagedSupport(UnmanagedBuildOperationWrapper.java:54)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:79)
    at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor.execute(RunAsBuildOperationBuildActionExecutor.java:57)
    at org.gradle.tooling.internal.provider.ContinuousBuildActionExecutor.execute(ContinuousBuildActionExecutor.java:103)
    at org.gradle.tooling.internal.provider.SubscribableBuildActionExecutor.execute(SubscribableBuildActionExecutor.java:64)
    at org.gradle.internal.session.DefaultBuildSessionContext.execute(DefaultBuildSessionContext.java:46)
    at org.gradle.tooling.internal.provider.BuildSessionLifecycleBuildActionExecuter.lambda$execute$0(BuildSessionLifecycleBuildActionExecuter.java:55)
    at org.gradle.internal.session.BuildSessionState.run(BuildSessionState.java:69)
    at org.gradle.tooling.internal.provider.BuildSessionLifecycleBuildActionExecuter.execute(BuildSessionLifecycleBuildActionExecuter.java:54)
    at org.gradle.tooling.internal.provider.BuildSessionLifecycleBuildActionExecuter.execute(BuildSessionLifecycleBuildActionExecuter.java:36)
    at org.gradle.tooling.internal.provider.GradleThreadBuildActionExecuter.execute(GradleThreadBuildActionExecuter.java:36)
    at org.gradle.tooling.internal.provider.GradleThreadBuildActionExecuter.execute(GradleThreadBuildActionExecuter.java:25)
    at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:63)
    at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:31)
    at org.gradle.tooling.internal.provider.SessionFailureReportingActionExecuter.execute(SessionFailureReportingActionExecuter.java:58)
    at org.gradle.tooling.internal.provider.SessionFailureReportingActionExecuter.execute(SessionFailureReportingActionExecuter.java:42)
    at org.gradle.tooling.internal.provider.SetupLoggingActionExecuter.execute(SetupLoggingActionExecuter.java:47)
    at org.gradle.tooling.internal.provider.SetupLoggingActionExecuter.execute(SetupLoggingActionExecuter.java:31)
    at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:65)
    at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
    at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:39)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
    at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:29)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
    at org.gradle.launcher.daemon.server.exec.RequestStopIfSingleUsedDaemon.execute(RequestStopIfSingleUsedDaemon.java:35)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
    at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.create(ForwardClientInput.java:78)
    at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.create(ForwardClientInput.java:75)
    at org.gradle.util.internal.Swapper.swap(Swapper.java:38)
    at org.gradle.launcher.daemon.server.exec.ForwardClientInput.execute(ForwardClientInput.java:75)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
    at org.gradle.launcher.daemon.server.exec.LogAndCheckHealth.execute(LogAndCheckHealth.java:55)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
    at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:63)
    at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
    at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:84)
    at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104)
    at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy$1.run(StartBuildOrRespondWithBusy.java:52)
    at org.gradle.launcher.daemon.server.DaemonStateCoordinator$1.run(DaemonStateCoordinator.java:297)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
Caused by: org.gradle.api.internal.plugins.PluginApplicationException: Failed to apply plugin 'de.set.ecj'.
    at org.gradle.api.internal.plugins.DefaultPluginManager.doApply(DefaultPluginManager.java:173)
    at org.gradle.api.internal.plugins.DefaultPluginManager.apply(DefaultPluginManager.java:146)
    at org.gradle.plugin.use.internal.DefaultPluginRequestApplicator.lambda$applyLegacyPlugins$2(DefaultPluginRequestApplicator.java:140)
    at org.gradle.plugin.use.internal.DefaultPluginRequestApplicator.applyPlugin(DefaultPluginRequestApplicator.java:185)
    ... 141 more
Caused by: org.gradle.api.plugins.PluginInstantiationException: Could not create plugin of type 'EclipseCompilerPlugin'.
    at org.gradle.api.internal.plugins.DefaultPluginManager.instantiatePlugin(DefaultPluginManager.java:83)
    at org.gradle.api.internal.plugins.DefaultPluginManager.producePluginInstance(DefaultPluginManager.java:206)
    at org.gradle.api.internal.plugins.DefaultPluginManager.addPlugin(DefaultPluginManager.java:182)
    at org.gradle.api.internal.plugins.DefaultPluginManager.access$100(DefaultPluginManager.java:52)
    at org.gradle.api.internal.plugins.DefaultPluginManager$AddPluginBuildOperation.run(DefaultPluginManager.java:282)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:75)
    at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:68)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:153)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:68)
    at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:56)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.lambda$run$1(DefaultBuildOperationExecutor.java:74)
    at org.gradle.internal.operations.UnmanagedBuildOperationWrapper.runWithUnmanagedSupport(UnmanagedBuildOperationWrapper.java:45)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:74)
    at org.gradle.api.internal.plugins.DefaultPluginManager.lambda$doApply$0(DefaultPluginManager.java:167)
    at org.gradle.configuration.internal.DefaultUserCodeApplicationContext.apply(DefaultUserCodeApplicationContext.java:44)
    at org.gradle.api.internal.plugins.DefaultPluginManager.doApply(DefaultPluginManager.java:166)
    ... 144 more
Caused by: org.gradle.internal.instantiation.ClassGenerationException: Could not generate a decorated class for type EclipseCompilerPlugin.
    at org.gradle.internal.instantiation.generator.AbstractClassGenerator.generateUnderLock(AbstractClassGenerator.java:242)
    at org.gradle.cache.internal.DefaultCrossBuildInMemoryCacheFactory$AbstractCrossBuildInMemoryCache.get(DefaultCrossBuildInMemoryCacheFactory.java:130)
    at org.gradle.internal.instantiation.generator.AbstractClassGenerator.generate(AbstractClassGenerator.java:167)
    at org.gradle.internal.instantiation.generator.AsmBackedClassGenerator.generate(AsmBackedClassGenerator.java:130)
    at org.gradle.internal.instantiation.generator.Jsr330ConstructorSelector.lambda$forType$0(Jsr330ConstructorSelector.java:56)
    at org.gradle.cache.Cache.lambda$get$0(Cache.java:31)
    at org.gradle.cache.internal.DefaultCrossBuildInMemoryCacheFactory$AbstractCrossBuildInMemoryCache.get(DefaultCrossBuildInMemoryCacheFactory.java:130)
    at org.gradle.cache.Cache.get(Cache.java:31)
    at org.gradle.internal.instantiation.generator.Jsr330ConstructorSelector.forType(Jsr330ConstructorSelector.java:53)
    at org.gradle.internal.instantiation.generator.Jsr330ConstructorSelector.forParams(Jsr330ConstructorSelector.java:48)
    at org.gradle.internal.instantiation.generator.DependencyInjectingInstantiator.doCreate(DependencyInjectingInstantiator.java:61)
    at org.gradle.internal.instantiation.generator.DependencyInjectingInstantiator.newInstance(DependencyInjectingInstantiator.java:55)
    at org.gradle.api.internal.plugins.DefaultPluginManager.instantiatePlugin(DefaultPluginManager.java:81)
    ... 161 more
Caused by: java.lang.NoClassDefFoundError: org/gradle/jvm/toolchain/JavaToolChain
    at org.gradle.internal.reflect.ClassInspector.inspectClass(ClassInspector.java:70)
    at org.gradle.internal.reflect.ClassInspector.visitGraph(ClassInspector.java:56)
    at org.gradle.internal.reflect.ClassInspector.inspect(ClassInspector.java:36)
    at org.gradle.internal.instantiation.generator.AbstractClassGenerator.inspectType(AbstractClassGenerator.java:271)
    at org.gradle.internal.instantiation.generator.AbstractClassGenerator.generateUnderLock(AbstractClassGenerator.java:210)
    ... 173 more
Caused by: java.lang.ClassNotFoundException: org.gradle.jvm.toolchain.JavaToolChain
    ... 178 more

* Get more help at https://help.gradle.org

BUILD FAILED in 124ms

[mopk]

JavaToolChain had been deprecated for quite some time and went when Gradle 7.x released.

Please, compare: https://github.com/gradle/gradle/tree/v6.9.1/subprojects/platform-jvm/src/main/java/org/gradle/jvm/toolchain (JavaToolChain.java is present) https://github.com/gradle/gradle/tree/v7.0.0/subprojects/platform-jvm/src/main/java/org/gradle/jvm/toolchain (no JavaToolChain.java)

Looks like it's time to convert the plugin from 'software model' API to the contemporary one.

[jjohannes]

Unfortunately, Gradle does not yet offer a good replacement for the removed (half baked) API: https://github.com/gradle/gradle/issues/15942

[liblit]

Gradle's API changes certainly don't make it easy, but one can still create Java compilation tasks that use ECJ. Here's how I define a JavaCompileUsingEcj task in a large project that I co-maintain, and here's how I put that task to work creating one JavaCompileUsingEcj task instance for each Java source set. Note that I am not replacing the standard tasks, such as compileJava and compileTestJava. Rather, I am adding tasks that recompile the same sources using ECJ. For this project, we want to use the standard compiler for building distributable artifacts, but we also compile using ECJ for extra static linting/checking.

[jjohannes]

Thanks for sharing the solution @liblit. I think you do not necessarily need this:

// Advise Gradle that this task will not be using the Java compilation API associated with the
// standard Java toolchain.  Instead, we will use an external compiler command, configured below.
javaCompiler.set(project.provider { null })

If I am not mistaken, Gradle will ignore the toolchain configuration if you explicitly set an executable the fork options (which you do). So I think you do not necessarily need to extend the JavaCompile task, but can register another instance of it and do all the configuration there. That would be a bit "cleaner" (if it works).

[jjohannes]

The solution was not suitable for the project I need this for, as everything needed to be done with ECJ since some code only compiles with ECJ (certain generics stuff). The project is quite large so forking a new compiler process for each subproject had quite a performance impact.

What we ended up doing now is copying the implementation on JavaCompile and replacing the implementation of the Compiler interface in createCompiler() with one that delegates to the ECJ compiler. This is similar to the pre Gradle 7 solution, using more internal API. I think it is quite fragile as it may break down as soon as internals around the JavaCompile task change. Right now it works with all Gradle 7.x releases so far.

Since we have a new task, we needed to register it separately - similar to @liblit's solution. We then deactivated the standard compile tasks completely.

[liblit]

@jjohannes wrote:

Thanks for sharing the solution @liblit. I think you do not necessarily need this:

// Advise Gradle that this task will not be using the Java compilation API associated with the
// standard Java toolchain.  Instead, we will use an external compiler command, configured below.
javaCompiler.set(project.provider { null })

If I am not mistaken, Gradle will ignore the toolchain configuration if you explicitly set an executable the fork options (which you do).

You're right, so I have removed this unnecessary step. Thanks!