Java vaadin初学者-变得严重：为servlet错误分配异常

我创建了一个test vaadin项目——当我尝试在本地Tomcat 7服务器上运行它时，我得到的错误就是这个---

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我做错了什么？我只是使用新建项目向导创建了一个Vaadin项目……我甚至没有向其中添加/编辑任何代码。

检查“com.anyaservices.spinthebattle.App_Main”路径是否指向有效的Java文件，该文件包含扩展Vaadin应用程序类的公共类。

此处缺少大量信息。试着在这里发布相关的东西，比如web.xml。另外，这是唯一的stacktrace，还是您有另一个包含更多信息的stacktrace？

 SEVERE: Allocate exception for servlet Spin the Bottle
javax.servlet.ServletException: Failed to load application class: com.anyaservices.spinthebottle.App_Main
at     com.vaadin.terminal.gwt.server.ApplicationServlet.init(ApplicationServlet.java:71)
at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1266)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1185)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:857)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:135)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)