遵循 Youtube Direct 的“入门”说明后，在尝试了 Eclipse、jdks 和插件的大量组合后，我无法让本地服务器运行。下面的错误让我这几天有点困惑。任何帮助表示赞赏，谢谢。
1/02/2013 11:26:00 AM com.google.apphosting.utils.jetty.JettyLogger info
INFO: Logging to JettyLogger(null) via com.google.apphosting.utils.jetty.JettyLogger
01/02/2013 11:26:00 AM com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
INFO: Successfully processed C:\Users\R\workspace\ytd\war\WEB-INF/appengine-web.xml
01/02/2013 11:26:00 AM com.google.apphosting.utils.config.AbstractConfigXmlReader readConfigXml
INFO: Successfully processed C:\Users\R\workspace\ytd\war\WEB-INF/web.xml
01/02/2013 11:26:00 AM com.google.appengine.tools.development.SystemPropertiesManager setSystemProperties
INFO: Overwriting system property key 'java.util.logging.config.file', value 'C:\Users\R\Documents\Eclipse EE\eclipse\plugins\com.google.appengine.eclipse.sdkbundle_1.7.4\appengine-java-sdk-1.7.4\config\sdk\logging.properties' with value 'WEB-INF/logging.properties' from 'C:\Users\R\workspace\ytd\war\WEB-INF\appengine-web.xml'
01/02/2013 11:26:01 AM com.google.apphosting.utils.jetty.JettyLogger info
INFO: jetty-6.1.x
01/02/2013 11:26:01 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: failed com.google.appengine.tools.development.DevAppEngineWebAppContext@16614e7{/,C:\Users\R\workspace\ytd\war}: java.lang.UnsupportedClassVersionError: com/google/ytd/guice/GuiceServletConfig : Unsupported major.minor version 51.0
01/02/2013 11:26:01 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: failed JettyContainerService$ApiProxyHandler@e66f56: java.lang.UnsupportedClassVersionError: com/google/ytd/guice/GuiceServletConfig : Unsupported major.minor version 51.0
01/02/2013 11:26:01 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: Error starting handlers
java.lang.UnsupportedClassVersionError: com/google/ytd/guice/GuiceServletConfig : 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 java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at com.google.appengine.tools.development.IsolatedAppClassLoader.loadClass(IsolatedAppClassLoader.java:213)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at org.mortbay.jetty.handler.ContextHandler.loadClass(ContextHandler.java:1101)
at org.mortbay.jetty.webapp.WebXmlConfiguration.initListener(WebXmlConfiguration.java:630)
at org.mortbay.jetty.webapp.WebXmlConfiguration.initWebXmlElement(WebXmlConfiguration.java:368)
at org.mortbay.jetty.webapp.WebXmlConfiguration.initialize(WebXmlConfiguration.java:289)
at org.mortbay.jetty.webapp.WebXmlConfiguration.configure(WebXmlConfiguration.java:222)
at org.mortbay.jetty.webapp.WebXmlConfiguration.configureWebApp(WebXmlConfiguration.java:180)
at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1247)
at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)
at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
at org.mortbay.jetty.Server.doStart(Server.java:224)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:205)
at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:232)
at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:157)
at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:333)
at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:269)
at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:245)
01/02/2013 11:26:01 AM com.google.apphosting.utils.jetty.JettyLogger info
INFO: Started SelectChannelConnector@127.0.0.1:8888
01/02/2013 11:26:01 AM com.google.appengine.tools.development.DevAppServerImpl start
INFO: The server is running at http://localhost:8888/
01/02/2013 11:26:01 AM com.google.appengine.tools.development.DevAppServerImpl start
INFO: The admin console is running at http://localhost:8888/_ah/admin