Eclipseでアプリエンジンを使用してサンプルプログラムを実行しようとしています。このサイトの指示に従って Google プラグインをインストールします: https://developers.google.com/appengine/docs/java/gettingstarted/installing
チュートリアルに従ってください。しかし、何らかの理由でアプリが実行されません。次の間違いがあります：
14/12/2012 14:13:41 com.google.apphosting.utils.jetty.JettyLogger info
INFO: Logging to JettyLogger(null) via com.google.apphosting.utils.jetty.JettyLogger
14/12/2012 14:13:41 com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
INFO: Successfully processed C:\Users\rona\workspace\Guestbook\war\WEB-INF/appengine-web.xml
14/12/2012 14:13:41 com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
SEVERE: Received exception processing C:\Users\rona\workspace\Guestbook\war\WEB-INF/appengine-web.xml
com.google.apphosting.utils.config.AppEngineConfigException: appengine-web.xml does not contain a <threadsafe> element.
See http://code.google.com/appengine/docs/java/config/appconfig.html#Using_Concurrent_Requests for more information.
You probably want to enable concurrent requests.
at com.google.apphosting.utils.config.AppEngineWebXmlReader.readAppEngineWebXml(AppEngineWebXmlReader.java:79)
at com.google.apphosting.utils.config.EarHelper.readWebModule(EarHelper.java:130)
at com.google.appengine.tools.development.AbstractContainerService.loadAppEngineWebXml(AbstractContainerService.java:334)
at com.google.appengine.tools.development.JettyContainerService.initContext(JettyContainerService.java:160)
at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:227)
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)
com.google.apphosting.utils.config.AppEngineConfigException: Invalid appengine-web.xml(C:\Users\rona\workspace\Guestbook\war\WEB-INF/appengine-web.xml) - appengine-web.xml does not contain a <threadsafe> element.
See http://code.google.com/appengine/docs/java/config/appconfig.html#Using_Concurrent_Requests for more information.
You probably want to enable concurrent requests.
at com.google.apphosting.utils.config.EarHelper.readWebModule(EarHelper.java:132)
at com.google.appengine.tools.development.AbstractContainerService.loadAppEngineWebXml(AbstractContainerService.java:334)
at com.google.appengine.tools.development.JettyContainerService.initContext(JettyContainerService.java:160)
at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:227)
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)
アプリのコードは、まったく同じようにコピーされた Google 開発者からのものです。プログラムが別のコンピューターで実行されていることを知っています。私のインストールの何かがうまくいきません。