Nikita, I'm not sure if your code lines are just written request but they are really response like in your final email, but here goes.
I haven't written servlets themselves in a really long time. Too much time wasted redoing all the fancy stuff things like Spring and Struts already do for me. What I seem to remember is that this would make sense. flushBuffer() is used to periodically flush what is left in the response buffer that should go to the browser. If you haven't gotten the writer yet then the structures have not been initialized yet and would be null. If I remember correctly the flushBuffer() is called automatically at the end of a doGet/doPost call so unless you are trying to push partial content to the browser because you have a huge web page to display (100's+ of database records usually resulting in an HTML files of 2K+) then there isn't much reason to call it. The best I/O is generally perceived with less calls to flushBuffer() but the more in the buffer the more memory that is used. That's one of those performance type of things I won't get into. Chris Berthold IT Systems Analyst Commercial Refrigerator Door Company 941 . 371 . 8110 x 205 -----Original Message----- From: Nikita Tovstoles [mailto:[EMAIL PROTECTED] Sent: Thursday, May 04, 2006 11:35 AM To: Tomcat Users List Subject: Re: NPE: outputStream is null in InternalOutputBuffer - why? Answering my own question, and asking another: I have this line in finally{} of Servlet.processRequest(): response.flushBuffer(); //if response.getWriter() was never called, then this method call will result in NPE. Is this proper behavior or should I file a bug report? Nikita Tovstoles wrote: > Hi, > > I am load testing a webapp running on Tomcat 5.5.12 (windoze). Once in > a while I see the following in Tomcat's log: > > SEVERE: Servlet.service() for servlet StatusServlet threw exception > java.lang.NullPointerException > at > org.apache.coyote.http11.InternalOutputBuffer.realWriteBytes(InternalOutputB uffer.java:747) > > at > org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:403) > at > org.apache.coyote.http11.InternalOutputBuffer.flush(InternalOutputBuffer.jav a:305) > > at > org.apache.coyote.http11.Http11Processor.action(Http11Processor.java:990) > at org.apache.coyote.Response.action(Response.java:182) > at > org.apache.catalina.connector.OutputBuffer.doFlush(OutputBuffer.java:322) > at > org.apache.catalina.connector.OutputBuffer.flush(OutputBuffer.java:293) > at > org.apache.catalina.connector.Response.flushBuffer(Response.java:544) > at > org.apache.catalina.connector.ResponseFacade.flushBuffer(ResponseFacade.java :276) > > at com.eviltwin.servermanager.BaseServlet.processRequest(Unknown > Source) > at > com.eviltwin.servermanager.envserver.StatusServlet.processRequest(Unknown > Source) > at com.eviltwin.servermanager.BaseServlet.doGet(Unknown Source) > at javax.servlet.http.HttpServlet.service(HttpServlet.java:689) > at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) > at > org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application FilterChain.java:252) > > at > org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh ain.java:173) > > at > org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.ja va:213) > > at > org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.ja va:178) > > at > org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126 ) > > at > org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105 ) > > at > org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java :107) > > at > org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148) > > at > org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:868) > > at > org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processC onnection(Http11BaseProtocol.java:663) > > at > org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.jav a:527) > > at > org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWo rkerThread.java:80) > > at > org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.jav a:684) > > at java.lang.Thread.run(Thread.java:595) > > Looking at Tomcat's source code, it appears outputStream is null in > InternalOutputBuffer. I have the following code that runs once per > request: > > processRequest() > { > ///other work > finally{ > request.getWriter().println(someString); //can be up to 200-300 > chars long > request.getWriter().close(); > } > } > Could someone please explain: > > -Why is this NPE happening? > - Is it occurring during println() or close() (or somewhere else)? > -Any workaround / solution? > > thanks a lot > > -nikita > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
