task wrapper(type: Wrapper) {
    gradleVersion = '1.0-milestone-6'
}

./gradlew wrapper --stacktrace
:wrapper

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':wrapper'.
Cause: org/gradle/wrapper/GradleWrapperMain

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

* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':wrapper'.
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:71)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:48)
	at org.gradle.api.internal.tasks.execution.PostExecutionAnalysisTaskExecuter.execute(PostExecutionAnalysisTaskExecuter.java:34)
	at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:55)
	at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:57)
	at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:41)
	at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:51)
	at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:52)
	at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:42)
	at org.gradle.api.internal.AbstractTask.executeWithoutThrowingTaskFailure(AbstractTask.java:243)
	at org.gradle.execution.DefaultTaskGraphExecuter.executeTask(DefaultTaskGraphExecuter.java:192)
	at org.gradle.execution.DefaultTaskGraphExecuter.doExecute(DefaultTaskGraphExecuter.java:177)
	at org.gradle.execution.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:83)
	at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:36)
	at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:70)
	at org.gradle.execution.DefaultBuildExecuter.access$300(DefaultBuildExecuter.java:23)
	at org.gradle.execution.DefaultBuildExecuter$2.proceed(DefaultBuildExecuter.java:80)
	at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:32)
	at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:70)
	at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:63)
	at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:157)
	at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:112)
	at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:80)
	at org.gradle.launcher.cli.RunBuildAction.execute(RunBuildAction.java:42)
	at org.gradle.launcher.cli.RunBuildAction.execute(RunBuildAction.java:28)
	at org.gradle.launcher.exec.ExceptionReportingAction.execute(ExceptionReportingAction.java:32)
	at org.gradle.launcher.exec.ExceptionReportingAction.execute(ExceptionReportingAction.java:21)
	at org.gradle.launcher.cli.CommandLineActionFactory$WithLoggingAction.execute(CommandLineActionFactory.java:233)
	at org.gradle.launcher.cli.CommandLineActionFactory$WithLoggingAction.execute(CommandLineActionFactory.java:217)
	at org.gradle.launcher.Main.doAction(Main.java:48)
	at org.gradle.launcher.exec.EntryPoint$1.execute(EntryPoint.java:53)
	at org.gradle.launcher.exec.EntryPoint$1.execute(EntryPoint.java:51)
	at org.gradle.launcher.exec.Execution.execute(Execution.java:28)
	at org.gradle.launcher.exec.EntryPoint.run(EntryPoint.java:39)
	at org.gradle.launcher.Main.main(Main.java:39)
	at org.gradle.launcher.ProcessBootstrap.runNoExit(ProcessBootstrap.java:51)
	at org.gradle.launcher.ProcessBootstrap.run(ProcessBootstrap.java:33)
	at org.gradle.launcher.GradleMain.main(GradleMain.java:24)
	at org.gradle.wrapper.BootstrapMainStarter.start(BootstrapMainStarter.java:33)
	at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:124)
	at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:53)
Caused by: java.lang.NoClassDefFoundError: org/gradle/wrapper/GradleWrapperMain
	at org.gradle.api.tasks.wrapper.Wrapper.generate(Wrapper.java:117)
	at org.gradle.api.internal.BeanDynamicObject.invokeMethod(BeanDynamicObject.java:158)
	at org.gradle.api.internal.CompositeDynamicObject.invokeMethod(CompositeDynamicObject.java:93)
	at org.gradle.api.tasks.wrapper.Wrapper_Decorated.invokeMethod(Unknown Source)
	at org.gradle.util.ReflectionUtil.invoke(ReflectionUtil.groovy:23)
	at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$2.execute(AnnotationProcessingTaskFactory.java:129)
	at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$2.execute(AnnotationProcessingTaskFactory.java:127)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:63)
	... 40 more
Caused by: java.lang.ClassNotFoundException: org.gradle.wrapper.GradleWrapperMain
	... 48 more


BUILD FAILED