无法使用Eclipse创建MapReduce项目

Question

I'm trying to create a MapReduce project for the first time with Eclipse Luna, but unable to do so. I'm getting the following exception in a pop-up.

"The selected wizard could not be started. Plug-in org.apache.hadoop.eclipse was unable to load class org.apache.hadoop.eclipse.NewMapReduceProjectWizard. org/apache/hadoop/eclipse/NewMapReduceProjectWizard : Unsupported major.minor version 51.0"

I'm using jdk1.6.0_31 and have set the 'compiler compliance level' to 1.6 in the eclipse-preferences as well. My eclipse version is Luna Service Release 1a (4.4.1). I'm also using the MapReduce plugin for Hadoop (version 0.18).

I also get a "Unhandled event loop exception" exception when trying to select the MapReduce perspective in Eclipse. Below are the details of the exception. Thanking you in advance!

    org.eclipse.e4.core.di.InjectionException: java.lang.RuntimeException: org.eclipse.core.runtime.CoreException: Plug-in org.apache.hadoop.eclipse was unable to load class org.apache.hadoop.eclipse.HadoopPerspectiveFactory.
    at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:62)
    at org.eclipse.e4.core.internal.di.InjectorImpl.invokeUsingClass(InjectorImpl.java:247)
    at org.eclipse.e4.core.internal.di.InjectorImpl.invoke(InjectorImpl.java:229)
    at org.eclipse.e4.core.contexts.ContextInjectionFactory.invoke(ContextInjectionFactory.java:132)
    at org.eclipse.e4.core.commands.internal.HandlerServiceHandler.execute(HandlerServiceHandler.java:149)
    at org.eclipse.core.commands.Command.executeWithChecks(Command.java:499)
    at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:508)
    at org.eclipse.e4.core.commands.internal.HandlerServiceImpl.executeHandler(HandlerServiceImpl.java:210)
    at org.eclipse.e4.core.commands.internal.HandlerServiceImpl.executeHandler(HandlerServiceImpl.java:196)
    at org.eclipse.e4.ui.workbench.addons.perspectiveswitcher.PerspectiveSwitcher.selectPerspective(PerspectiveSwitcher.java:661)
    at org.eclipse.e4.ui.workbench.addons.perspectiveswitcher.PerspectiveSwitcher.access$7(PerspectiveSwitcher.java:657)
    at org.eclipse.e4.ui.workbench.addons.perspectiveswitcher.PerspectiveSwitcher$11.widgetSelected(PerspectiveSwitcher.java:417)
    at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:248)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4353)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1061)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4172)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3761)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1151)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1032)
    at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:148)
    at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:636)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:579)
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
    at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:135)
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:380)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:235)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:648)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:603)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1465)
Caused by: java.lang.RuntimeException: org.eclipse.core.runtime.CoreException: Plug-in org.apache.hadoop.eclipse was unable to load class org.apache.hadoop.eclipse.HadoopPerspectiveFactory.
    at org.eclipse.ui.internal.registry.PerspectiveDescriptor.createFactory(PerspectiveDescriptor.java:78)
    at org.eclipse.ui.internal.WorkbenchPage.setPerspective(WorkbenchPage.java:4032)
    at org.eclipse.ui.handlers.ShowPerspectiveHandler.openPerspective(ShowPerspectiveHandler.java:147)
    at org.eclipse.ui.handlers.ShowPerspectiveHandler.openOther(ShowPerspectiveHandler.java:119)
    at org.eclipse.ui.handlers.ShowPerspectiveHandler.execute(ShowPerspectiveHandler.java:58)
    at org.eclipse.ui.internal.handlers.HandlerProxy.execute(HandlerProxy.java:294)
    at org.eclipse.ui.internal.handlers.E4HandlerProxy.execute(E4HandlerProxy.java:90)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:55)
    ... 38 more
Caused by: org.eclipse.core.runtime.CoreException: Plug-in org.apache.hadoop.eclipse was unable to load class org.apache.hadoop.eclipse.HadoopPerspectiveFactory.
    at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.throwException(RegistryStrategyOSGI.java:194)
    at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:178)
    at org.eclipse.core.internal.registry.ExtensionRegistry.createExecutableExtension(ExtensionRegistry.java:905)
    at org.eclipse.core.internal.registry.ConfigurationElement.createExecutableExtension(ConfigurationElement.java:243)
    at org.eclipse.core.internal.registry.ConfigurationElementHandle.createExecutableExtension(ConfigurationElementHandle.java:55)
    at org.eclipse.ui.internal.registry.PerspectiveDescriptor.createFactory(PerspectiveDescriptor.java:74)
    ... 49 more
Caused by: java.lang.UnsupportedClassVersionError: org/apache/hadoop/eclipse/HadoopPerspectiveFactory : Unsupported major.minor version 51.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.defineClass(ModuleClassLoader.java:285)
    at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.defineClass(ClasspathManager.java:632)
    at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findClassImpl(ClasspathManager.java:588)
    at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClassImpl(ClasspathManager.java:540)
    at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClass(ClasspathManager.java:527)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.findLocalClass(ModuleClassLoader.java:324)
    at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:320)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:395)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:345)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:337)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.loadClass(EquinoxBundle.java:568)
    at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:174)
    ... 53 more

Answer 1

'Unsupported major.minor version 51.0' means the code (in this case the hadoop plugin) was compiled with Java 1.7. You can't run this code with Java 1.6, you need to move to 1.7 (or 1.8).