google appengine for java初体验

Uncaught exception from servlet
java.lang.ClassCastException: java.security.AccessControlException cannot be cast to javax.servlet.ServletException
	at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:754)
	at org.apache.jsp.jsp.classloader_jsp._jspService(classloader_jsp.java:64)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
	at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
	at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:35)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
	at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
	at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
	at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
	at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
	at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:712)
	at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
	at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:237)
	at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
	at org.mortbay.jetty.Server.handle(Server.java:313)
	at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:506)
	at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:830)
	at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:63)
	at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381)
	at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:125)
	at com.google.apphosting.runtime.JavaRuntime.handleRequest(JavaRuntime.java:235)
	at com.google.apphosting.base.RuntimePb$EvaluationRuntime$6.handleBlockingRequest(RuntimePb.java:4547)
	at com.google.apphosting.base.RuntimePb$EvaluationRuntime$6.handleBlockingRequest(RuntimePb.java:4545)
	at com.google.net.rpc.impl.BlockingApplicationHandler.handleRequest(BlockingApplicationHandler.java:24)
	at com.google.net.rpc.impl.RpcUtil.runRpcInApplication(RpcUtil.java:359)
	at com.google.net.rpc.impl.Server$2.run(Server.java:792)
	at com.google.tracing.LocalTraceSpanRunnable.run(LocalTraceSpanRunnable.java:56)
	at com.google.tracing.LocalTraceSpanBuilder.internalContinueSpan(LocalTraceSpanBuilder.java:489)
	at com.google.net.rpc.impl.Server.startRpc(Server.java:748)
	at com.google.net.rpc.impl.Server.processRequest(Server.java:340)
	at com.google.net.rpc.impl.ServerConnection.messageReceived(ServerConnection.java:422)
	at com.google.net.rpc.impl.RpcConnection.parseMessages(RpcConnection.java:319)
	at com.google.net.rpc.impl.RpcConnection.dataReceived(RpcConnection.java:290)
	at com.google.net.async.Connection.handleReadEvent(Connection.java:419)
	at com.google.net.async.EventDispatcher.processNetworkEvents(EventDispatcher.java:733)
	at com.google.net.async.EventDispatcher.internalLoop(EventDispatcher.java:207)
	at com.google.net.async.EventDispatcher.loop(EventDispatcher.java:101)
	at com.google.net.rpc.RpcService.runUntilServerShutdown(RpcService.java:249)
	at com.google.apphosting.runtime.JavaRuntime$RpcRunnable.run(JavaRuntime.java:373)
	at java.lang.Thread.run(Unknown Source)

Unexpected exception from servlet: java.lang.ClassCastException: java.security.AccessControlException cannot be cast to javax.servlet.ServletException