from my error log, I found some time "response.getOutputStream()" return null, I am not sure if it is because of overtime, or other reason.
java.lang.NullPointerException at org.mortbay.io.ByteArrayBuffer.wrap(ByteArrayBuffer.java:151) at org.mortbay.jetty.AbstractGenerator$Output.write (AbstractGenerator.java:584) at com.witwall.commons.Util.downloadPdf(Util.java:34) at com.witwall.pdf.PdfDecryptSelvert.doPost(PdfDecryptSelvert.java: 298) at javax.servlet.http.HttpServlet.service(HttpServlet.java:713) at javax.servlet.http.HttpServlet.service(HttpServlet.java:806) at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java: 487) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter (ServletHandler.java:1093) at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter (ParseBlobUploadFilter.java:97) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter (ServletHandler.java:1084) at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter (SaveSessionFilter.java:35) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter (ServletHandler.java:1084) at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter (TransactionCleanupFilter.java:43) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter (ServletHandler.java:1084) at org.mortbay.jetty.servlet.ServletHandler.handle (ServletHandler.java:360) at org.mortbay.jetty.security.SecurityHandler.handle (SecurityHandler.java:216) at org.mortbay.jetty.servlet.SessionHandler.handle (SessionHandler.java:181) at org.mortbay.jetty.handler.ContextHandler.handle (ContextHandler.java:712) at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java: 405) at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle (AppVersionHandlerMap.java:238) at org.mortbay.jetty.handler.HandlerWrapper.handle (HandlerWrapper.java:139) at org.mortbay.jetty.Server.handle(Server.java:313) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java: 506) at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete (HttpConnection.java:830) at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable (RpcRequestParser.java:76) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381) at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest (JettyServletEngineAdapter.java:135) at com.google.apphosting.runtime.JavaRuntime.handleRequest (JavaRuntime.java:235) at com.google.apphosting.base.RuntimePb$EvaluationRuntime $6.handleBlockingRequest(RuntimePb.java:5235) at com.google.apphosting.base.RuntimePb$EvaluationRuntime $6.handleBlockingRequest(RuntimePb.java:5233) at com.google.net.rpc.impl.BlockingApplicationHandler.handleRequest (BlockingApplicationHandler.java:24) at com.google.net.rpc.impl.RpcUtil.runRpcInApplication(RpcUtil.java: 363) at com.google.net.rpc.impl.Server$2.run(Server.java:838) at com.google.tracing.LocalTraceSpanRunnable.run (LocalTraceSpanRunnable.java:56) at com.google.tracing.LocalTraceSpanBuilder.internalContinueSpan (LocalTraceSpanBuilder.java:536) at com.google.net.rpc.impl.Server.startRpc(Server.java:793) at com.google.net.rpc.impl.Server.processRequest(Server.java:368) at com.google.net.rpc.impl.ServerConnection.messageReceived (ServerConnection.java:448) at com.google.net.rpc.impl.RpcConnection.parseMessages (RpcConnection.java:319) at com.google.net.rpc.impl.RpcConnection.dataReceived (RpcConnection.java:290) at com.google.net.async.Connection.handleReadEvent(Connection.java: 466) at com.google.net.async.EventDispatcher.processNetworkEvents (EventDispatcher.java:759) at com.google.net.async.EventDispatcher.internalLoop (EventDispatcher.java:205) at com.google.net.async.EventDispatcher.loop(EventDispatcher.java: 101) at com.google.net.rpc.RpcService.runUntilServerShutdown (RpcService.java:251) at com.google.apphosting.runtime.JavaRuntime$RpcRunnable.run (JavaRuntime.java:394) at java.lang.Thread.run(Unknown Source) -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appeng...@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.