Java 无法使AppEngine在Eclipse中工作

嘿，伙计们，我遵循GWT开发者指南，到目前为止，一切都很好，直到我尝试使用AppEngine。 我在MacOS X 10.7.5上安装了最新的JDK和Eclipse。 如果我尝试运行股票交易教程程序，则会出现以下错误：

objc[377]: Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.7.0_40.jdk/Contents/Home/bin/java and /Library/Java/JavaVirtualMachines/jdk1.7.0_40.jdk/Contents/Home/jre/lib/libinstrument.dylib. One of the two will be used. Which one is undefined.
Initializing App Engine server
Okt 07, 2013 10:24:00 PM com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
Information: Successfully processed /Users/HP/Desktop/StockWatcher/war/WEB-INF/appengine-web.xml
Okt 07, 2013 10:24:00 PM com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
Schwerwiegend: Received exception processing /Users/HP/Desktop/StockWatcher/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:85)
    at com.google.apphosting.utils.config.EarHelper.readWebModule(EarHelper.java:166)
    at com.google.appengine.tools.development.ApplicationConfigurationManager$WarModuleConfigurationHandle.readConfiguration(ApplicationConfigurationManager.java:399)
    at com.google.appengine.tools.development.ApplicationConfigurationManager.<init>(ApplicationConfigurationManager.java:146)
    at com.google.appengine.tools.development.ApplicationConfigurationManager.newWarConfigurationManager(ApplicationConfigurationManager.java:88)
    at com.google.appengine.tools.development.DevAppServerImpl.<init>(DevAppServerImpl.java:139)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at com.google.appengine.tools.development.DevAppServerFactory.doCreateDevAppServer(DevAppServerFactory.java:258)
    at com.google.appengine.tools.development.DevAppServerFactory.access$000(DevAppServerFactory.java:36)
    at com.google.appengine.tools.development.DevAppServerFactory$1.run(DevAppServerFactory.java:226)
    at com.google.appengine.tools.development.DevAppServerFactory$1.run(DevAppServerFactory.java:224)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer(DevAppServerFactory.java:224)
    at com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer(DevAppServerFactory.java:76)
    at com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer(DevAppServerFactory.java:60)
    at com.google.appengine.tools.development.gwt.AppEngineLauncher.start(AppEngineLauncher.java:84)
    at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:509)
    at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1093)
    at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:836)
    at com.google.gwt.dev.DevMode.main(DevMode.java:311)

   [ERROR] Unable to start App Engine server
com.google.apphosting.utils.config.AppEngineConfigException: Invalid configuration
    at com.google.appengine.tools.development.DevAppServerImpl.reportDeferredConfigurationException(DevAppServerImpl.java:445)
    at com.google.appengine.tools.development.DevAppServerImpl.doStart(DevAppServerImpl.java:225)
    at com.google.appengine.tools.development.DevAppServerImpl.access$000(DevAppServerImpl.java:47)
    at com.google.appengine.tools.development.DevAppServerImpl$1.run(DevAppServerImpl.java:212)
    at com.google.appengine.tools.development.DevAppServerImpl$1.run(DevAppServerImpl.java:210)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:210)
    at com.google.appengine.tools.development.gwt.AppEngineLauncher.start(AppEngineLauncher.java:97)
    at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:509)
    at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1093)
    at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:836)
    at com.google.gwt.dev.DevMode.main(DevMode.java:311)
Caused by: com.google.apphosting.utils.config.AppEngineConfigException: Invalid appengine-web.xml(/Users/HP/Desktop/StockWatcher/war/WEB-INF/appengine-web.xml) - appengine-web.xml does not contain a <threadsafe> element.
See http://code.google.com/appengine/docs/java/config/appconfig.html#Using_Concurrent_Requests for more information.
You probably want to enable concurrent requests.
    at com.google.apphosting.utils.config.EarHelper.readWebModule(EarHelper.java:168)
    at com.google.appengine.tools.development.ApplicationConfigurationManager$WarModuleConfigurationHandle.readConfiguration(ApplicationConfigurationManager.java:399)
    at com.google.appengine.tools.development.ApplicationConfigurationManager.<init>(ApplicationConfigurationManager.java:146)
    at com.google.appengine.tools.development.ApplicationConfigurationManager.newWarConfigurationManager(ApplicationConfigurationManager.java:88)
    at com.google.appengine.tools.development.DevAppServerImpl.<init>(DevAppServerImpl.java:139)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at com.google.appengine.tools.development.DevAppServerFactory.doCreateDevAppServer(DevAppServerFactory.java:258)
    at com.google.appengine.tools.development.DevAppServerFactory.access$000(DevAppServerFactory.java:36)
    at com.google.appengine.tools.development.DevAppServerFactory$1.run(DevAppServerFactory.java:226)
    at com.google.appengine.tools.development.DevAppServerFactory$1.run(DevAppServerFactory.java:224)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer(DevAppServerFactory.java:224)
    at com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer(DevAppServerFactory.java:76)
    at com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer(DevAppServerFactory.java:60)
    at com.google.appengine.tools.development.gwt.AppEngineLauncher.start(AppEngineLauncher.java:84)
    ... 4 more
Unable to start embedded HTTP server
com.google.gwt.core.ext.UnableToCompleteException: (see previous log entries)
    at com.google.appengine.tools.development.gwt.AppEngineLauncher.start(AppEngineLauncher.java:102)
    at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:509)
    at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1093)
    at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:836)
    at com.google.gwt.dev.DevMode.main(DevMode.java:311)
[ERROR] shell failed in doStartupServer method

objc[377]：JavaLaunchHelper类在/Library/Java/JavaVirtualMachines/jdk1.7.0_40.jdk/Contents/Home/bin/Java和/Library/Java/JavaVirtualMachines/jdk1.7.0_40.jdk/Contents/Home/libinstrument.dylib中实现。将使用其中一个。哪一个是未定义的。
正在初始化应用程序引擎服务器
2013年12月7日10:24:00 PM com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
信息：已成功处理/Users/HP/Desktop/StockWatcher/war/WEB-INF/appengine-WEB.xml
2013年12月7日10:24:00 PM com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
Schwerwiegend:收到异常处理/Users/HP/Desktop/StockWatcher/war/WEB-INF/appengine-WEB.xml
com.google.apphosting.utils.config.appengineconfig异常：appengine-web.xml不包含元素。
看见http://code.google.com/appengine/docs/java/config/appconfig.html#Using_Concurrent_Requests 了解更多信息。
您可能希望启用并发请求。
位于com.google.apphosting.utils.config.AppEngineWebXmlReader.readAppEngineWebXml（AppEngineWebXmlReader.java:85）
位于com.google.apphosting.utils.config.earheloper.readWebModule（earheloper.java:166）
位于com.google.appengine.tools.development.ApplicationConfigurationManager$WarModuleConfigurationHandle.readConfiguration（ApplicationConfigurationManager.java:399）
位于com.google.appengine.tools.development.ApplicationConfiguration Manager（ApplicationConfiguration Manager.java:146）
位于com.google.appengine.tools.development.ApplicationConfiguration Manager.NewWarConfiguration Manager（ApplicationConfiguration Manager.java:88）
位于com.google.appengine.tools.development.DevAppServerImpl.（DevAppServerImpl.java:139）
位于sun.reflect.NativeConstructorAccessorImpl.newInstance0（本机方法）
位于sun.reflect.NativeConstructorAccessorImpl.newInstance（NativeConstructorAccessorImpl.java:57）
在sun.reflect.DelegatingConstructorAccessorImpl.newInstance（DelegatingConstructorAccessorImpl.java:45）
位于java.lang.reflect.Constructor.newInstance（Constructor.java:526）
位于com.google.appengine.tools.development.DevAppServerFactory.doCreateDevAppServer（DevAppServerFactory.java:258）
在com.google.appengine.tools.development.DevAppServerFactory.access$000（DevAppServerFactory.java:36）
位于com.google.appengine.tools.development.DevAppServerFactory$1.run（DevAppServerFactory.java:226）
在com.google.appengine.tools.development.DevAppServerFactory$1.run（DevAppServerFactory.java:224）
位于java.security.AccessController.doPrivileged（本机方法）
在com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer（DevAppServerFactory.java:224）
在com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer（DevAppServerFactory.java:76）
在com.google.appengine.tools.development.DevAppServerFactory.createDevAppServer（DevAppServerFactory.java:60）
位于com.google.appengine.tools.development.gwt.AppEngineLauncher.start（AppEngineLauncher.java:84）
位于com.google.gwt.dev.DevMode.doStartUpServer（DevMode.java:509）
位于com.google.gwt.dev.DevModeBase.startUp（DevModeBase.java:1093）
位于com.google.gwt.dev.DevModeBase.run（DevModeBase.java:836）
位于com.google.gwt.dev.DevMode.main（DevMode.java:311）
[错误]无法启动应用程序引擎服务器
com.google.apphosting.utils.config.appengineconfig异常：配置无效
位于com.google.appengine.tools.development.DevAppServerImpl.reportDeferredConfigurationException（DevAppServerImpl.java:445）
在com.google.appengine.tools.development.DevAppServerImpl.doStart（DevAppServerImpl.java:225）
位于com.google.appengine.tools.development.DevAppServerImpl.access$000（DevAppServerImpl.java:47）
位于com.google.appengine.tools.development.DevAppServerImpl$1.run（DevAppServerImpl.java:212）
位于com.google.appengine.tools.development.DevAppServerImpl$1.run（DevAppServerImpl.java:210）
位于java.security.AccessController.doPrivileged（本机方法）
位于com.google.appengine.tools.development.DevAppServerImpl.start（DevAppServerImpl.java:210）
位于com.google.appengine.tools.development.gwt.AppEngineLauncher.start（AppEngineLauncher.java:97）
位于com.google.gwt.dev.DevMode.doStartUpServer（DevMode.java:509）
位于com.google.gwt.dev.DevModeBase.startUp（DevModeBase.java:1093）
位于com.google.gwt.dev.DevModeBase.run（DevModeBase.java:836）
位于com.google.gwt.dev.DevMode.main（DevMode.java:311）
原因：com.google.apphosting.utils.config.appengineconfig异常：无效的appengine web.xml（/Users/HP/Desktop/StockWatcher/war/web-INF/appengine web.xml）-appengine-web.xml不包含元素。
看见http://code.google.com/appengine/docs/java/config/appconfig.html#Using_Concurrent_Requests 了解更多信息。
您可能希望启用并发请求。
位于com.google.apphosting.utils.config.earheloper.readWebModule（earheloper.java:168）
位于com.google.appengine.tools.development.ApplicationConfigurationManager$WarModuleConfigurationHandle.readConfiguration（ApplicationConfigurationManager.java:399）
位于com.google.appengine.tools.development.ApplicationConfiguration Manager（ApplicationConfiguration Manager.java:146）
位于com.google.appengine.tools.development.ApplicationConfiguration Manager.NewWarConfiguration Manager（ApplicationConfiguration Manager.java:88）
位于com.google.appengine.tools.development.DevAppServerImpl.（DevAppServerImpl.java:139）
位于sun.reflect.NativeConstructorAccessorImpl.newInstance0（本机方法）
位于sun.reflect.NativeConstructorAccessorImpl.newInstance（NativeConstructorAccessorImpl.java:57）
在sun.reflect.DelegatingConstructorAccessorImpl.newInstance（DelegatingConstructorAccessor
<threadsafe>false</threadsafe> 

/Users/HP/Desktop/StockWatcher/war/WEB-INF/appengine-web.xml