错误信息如下：
org.eclipse.core.runtime.CoreException: Plug-in org.apache.hadoop.eclipse was unable to load class org.apache.hadoop.eclipse.launch.HadoopApplicationLaunchShortcut.
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.debug.internal.ui.launchConfigurations.LaunchShortcutExtension.getDelegate(LaunchShortcutExtension.java:410)
at org.eclipse.debug.internal.ui.launchConfigurations.LaunchShortcutExtension.launch(LaunchShortcutExtension.java:422)
at org.eclipse.debug.internal.ui.actions.LaunchShortcutAction.run(LaunchShortcutAction.java:70)
at org.eclipse.debug.internal.ui.actions.LaunchShortcutAction.runWithEvent(LaunchShortcutAction.java:121)
at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:584)
at org.eclipse.jface.action.ActionContributionItem.access$2(ActionContributionItem.java:501)
at org.eclipse.jface.action.ActionContributionItem$5.handleEvent(ActionContributionItem.java:411)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4165)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3754)
------解决方案--------------------------------------------------------
去网上搜一搜你的错误，有解决方案的。
------解决方案--------------------------------------------------------
http://www.codeweblog.com/hadoop-study-notes-five-use-of-eclipse-plug-in/
------解决方案--------------------------------------------------------
http://web.archiveorange.com/archive/v/AK8TeBiLO93kN0nddN18
http://mail-archives.apache.org/mod_mbox/hadoop-common-commits/200710.mbox/%3C20071025185908.E27A81A9832@eris.apache.org%3E
谷歌一搜很多,楼主你看看这种英文的论坛
------解决方案--------------------------------------------------------
------解决方案--------------------------------------------------------
?Hadoop installation directory specified
?Open the Map / Reduce views
?"Window" -> "Open Perspective" -> "Other" -> "Map / Reduce".
"Window" -> "Show views" -> "Other" -> "Map Reduce Tools" -> "Map / Reduce locations".
?New Hadoop location
?DFS view file browsing
?MapReduce jobs run
?View the results
楼主试试行不行吧。