the error is here:
org.apache.catalina.connector.ResponseFacade.encodeURL(ResponseFacade.java:398)
at org.apache.jsp.Test1_jsp._jspService(Test1_jsp.java:93) if you look in
/work/Catalina/localhost/WebAppName/org/apache/jsp/Test1_jsp.java
at line 93 you will see the offending line
you are creating an artificial response object instead of using the response
that is provided you via response
<% response.write("<em>this is a test in italics</em"); %>
hth
Martin Gainty
______________________________________________
Jogi és Bizalmassági kinyilatkoztatás/Verzicht und
Vertraulichkeitanmerkung/Note de déni et de confidentialité
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> Date: Wed, 15 Jun 2011 18:43:21 +0100
> From: p...@j-paine.org
> To: users@tomcat.apache.org
> Subject: Re: Null-pointer exception from response.encodeUrl under Windows
> Tomcat 7
>
> About a week ago, I reported what seemed like a sporadic null-pointer
> exception from response.encodeUrl. I've managed to simplify the code that
> provokes it, and will show it below. My original report, with details of
> the Tomcat version and so on, is after this mail.
>
> The error occurred in a large system I've written that uses servlets and
> JSP. It enables users to analyse certain kinds of numerical data over the
> Web, and uses sessions to hold information about those users currently
> using the system. Below is a JSP page I've constructed that demonstrates
> the error:
> <%@ page import="javax.servlet.*,javax.servlet.http.*,salco.*"%>
>
> <HTML>
> <HEAD>
>
> <TITLE>Test1</TITLE>
> </HEAD>
>
> <BODY BGCOLOR=white>
>
> <H1>Test1</H1>
>
> <%
> HttpSession this_session = request.getSession(true);
> out.println( "this_session = " + this_session + ".<BR>" );
>
> out.println( "Date = " + new java.util.Date() + ".<BR>" );
>
> ResponseHolder rh = (ResponseHolder)this_session.getAttribute(
> "response_holder" );
> out.println( "rh = " + rh + ".<BR>" );
> if ( rh == null ) {
> out.println( "rh is null.<BR>" );
> rh = new ResponseHolder( response );
> this_session.setAttribute( "response_holder", rh );
> this_session.setAttribute( "count", 0 );
> out.println( "<BR>count = 0.<BR>" );
> }
> else {
> int count = (Integer)this_session.getAttribute( "count" );
> out.println( "rh is not null.<BR>" );
> this_session.setAttribute( "count", count+1 );
> out.println( "<BR>count = " + (count+1) + ".<BR>" );
> }
>
> String result = "None yet";
> try {
> result = rh.response.encodeURL( "/Test1.jsp" );
> out.println( "Encoded URL OK: result = " + result + ".<BR>" );
> }
> catch ( java.lang.NullPointerException e ) {
> out.println( "Crashed while encoding URL: <BR>" );
> e.printStackTrace( new java.io.PrintWriter(out) );
> }
> %>
>
> </BODY>
> </HTML>
>
> This page starts by obtaining an instance of HTTPSession by calling
> request.getSession(true). This instance will have been created when the
> user logs in for their current session, by another call of
> request.getSession(true).
>
> The page then displays the date and time so that you can check that in my
> diagnostics, the times follow one another and I'm not repeating old
> output. It then tries to obtain an instance of a class I've defined named
> ResponseHolder, and does so by calling HttpSession.getAttribute.
> ResponseHolder is a class I wrote specially for this demo, and has one
> field, an HTTPServletResponse. In real life, I store users' session data
> in instances with many fields, of which an HTTPServletResponse is one. I
> pass these to my server-side code. This needs the HTTPServletResponse when
> doing such things as encoding URLs, which is why I include it. For the
> purposes of this test, the non-HTTPServletResponse fields aren't relevant,
> and so I've not included them in the ResponseHolder.
>
> If the ResponseHolder instance is null, it's probably because the page is
> being loaded for the first time in the session. In that case, I create a
> new ResponseHolder, and call HttpSession.setAttribute to store it.
>
> The page also maintains and displays a count. This is solely for this
> demo. As with displaying the time, it's a sanity check on the output. For
> example, it confirms that I actually have reloaded the page.
>
> The rest of the page calls encodeURL, and displays the result. If
> encodeURL crashes with a NullPointerException, it catches this and
> displays the stack trace instead.
>
> By the way, the page has three imports. Two are for the javax.servlet
> classes; the third is for my project classes.
>
> Next, here's my ResponseHolder class:
> package salco;
>
> import javax.servlet.*;
> import javax.servlet.http.*;
>
> public class ResponseHolder
> {
> public HttpServletResponse response;
>
> public ResponseHolder( HttpServletResponse r )
> {
> this.response = r;
> }
>
> public String toString()
> {
> return "[ResponseHolder " + this.response + "]";
> }
> }
>
> As mentioned earlier, it has just one field, the HttpServletResponse.
>
> Finally, I'll show output from three sets of transactions. To create
> these, I logged into the system, thereby creating a new session as
> explained above. I then loaded the JSP page, Test1.jsp, and kept reloading
> it. (This was in Firefox 4.0.1; but browser and browser version are
> probably not relevant. The error also occurs on Internet Explorer and
> Google Chrome.) I then copied the page shown by the browser into a text
> file, and appended new pages as I reloaded them. Here, then is my
> output. It's long, so be warned; to get to the end, search for "END OF
> OUTPUT":
>
> (FIRST SESSION)
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@9be2b5.
> Date = Wed Jun 15 17:46:45 BST 2011.
> rh = null.
> rh is null.
>
> count = 0.
> Encoded URL OK: result = /Test1.jsp.
>
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@9be2b5.
> Date = Wed Jun 15 17:46:55 BST 2011.
> rh = [ResponseHolder org.apache.catalina.connector.ResponseFacade@9c176c].
> rh is not null.
>
> count = 1.
> Crashed while encoding URL:
> java.lang.NullPointerException at
> org.apache.catalina.connector.Response.toAbsolute(Response.java:1594) at
> org.apache.catalina.connector.Response.encodeURL(Response.java:1198) at
> org.apache.catalina.connector.ResponseFacade.encodeURL(ResponseFacade.java:398)
>
> at org.apache.jsp.Test1_jsp._jspService(Test1_jsp.java:93) at
> org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at
> org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419)
>
> at
> org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
> at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333) at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at
> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
>
> at
> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
>
> at
> org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
>
> at
> org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
>
> at
> org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
> at
> org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
> at
> org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:563)
> at
> org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
>
> at
> org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:399)
> at
> org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:317)
> at
> org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:204)
>
> at
> org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:311)
>
> 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)
>
> ----
>
> (SECOND SESSION)
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@1ae9aaa.
> Date = Wed Jun 15 17:50:22 BST 2011.
> rh = null.
> rh is null.
>
> count = 0.
> Encoded URL OK: result = /Test1.jsp.
>
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@1ae9aaa.
> Date = Wed Jun 15 17:50:35 BST 2011.
> rh = [ResponseHolder
> org.apache.catalina.connector.ResponseFacade@1f8bd0d].
> rh is not null.
>
> count = 1.
> Encoded URL OK: result = /Test1.jsp.
>
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@1ae9aaa.
> Date = Wed Jun 15 17:50:46 BST 2011.
> rh = [ResponseHolder
> org.apache.catalina.connector.ResponseFacade@1f8bd0d].
> rh is not null.
>
> count = 2.
> Encoded URL OK: result = /Test1.jsp.
>
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@1ae9aaa.
> Date = Wed Jun 15 17:51:44 BST 2011.
> rh = [ResponseHolder
> org.apache.catalina.connector.ResponseFacade@1f8bd0d].
> rh is not null.
>
> count = 3.
> Encoded URL OK: result = /Test1.jsp.
>
>
> Was OK up to and including count=94, then:
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@1ae9aaa.
> Date = Wed Jun 15 17:53:53 BST 2011.
> rh = [ResponseHolder
> org.apache.catalina.connector.ResponseFacade@1f8bd0d].
> rh is not null.
>
> count = 95.
> Crashed while encoding URL:
> java.lang.NullPointerException at
> org.apache.catalina.connector.Response.toAbsolute(Response.java:1594) at
> org.apache.catalina.connector.Response.encodeURL(Response.java:1198) at
> org.apache.catalina.connector.ResponseFacade.encodeURL(ResponseFacade.java:398)
>
> at org.apache.jsp.Test1_jsp._jspService(Test1_jsp.java:93) at
> org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at
> org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419)
>
> at
> org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
> at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333) at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at
> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
>
> at
> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
>
> at
> org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
>
> at
> org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
>
> at
> org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
> at
> org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
> at
> org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:563)
> at
> org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
>
> at
> org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:399)
> at
> org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:317)
> at
> org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:204)
>
> at
> org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:311)
>
> 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)
>
> ----
>
> (THIRD SESSION)
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@c68a98.
> Date = Wed Jun 15 18:36:38 BST 2011.
> rh = null.
> rh is null.
>
> count = 0.
> Encoded URL OK: result = /Test1.jsp.
>
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@c68a98.
> Date = Wed Jun 15 18:36:53 BST 2011.
> rh = [ResponseHolder
> org.apache.catalina.connector.ResponseFacade@121b59a].
> rh is not null.
>
> count = 1.
> Encoded URL OK: result = /Test1.jsp.
>
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@c68a98.
> Date = Wed Jun 15 18:37:05 BST 2011.
> rh = [ResponseHolder
> org.apache.catalina.connector.ResponseFacade@121b59a].
> rh is not null.
>
> count = 2.
> Encoded URL OK: result = /Test1.jsp.
>
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@c68a98.
> Date = Wed Jun 15 18:37:17 BST 2011.
> rh = [ResponseHolder
> org.apache.catalina.connector.ResponseFacade@121b59a].
> rh is not null.
>
> count = 3.
> Encoded URL OK: result = /Test1.jsp.
>
> Was then OK up to and including count=49, then:
>
> Test1
> this_session = org.apache.catalina.session.StandardSessionFacade@c68a98.
> Date = Wed Jun 15 18:37:59 BST 2011.
> rh = [ResponseHolder
> org.apache.catalina.connector.ResponseFacade@121b59a].
> rh is not null.
>
> count = 50.
> Crashed while encoding URL:
> java.lang.NullPointerException at
> org.apache.catalina.connector.Response.toAbsolute(Response.java:1594) at
> org.apache.catalina.connector.Response.encodeURL(Response.java:1198) at
> org.apache.catalina.connector.ResponseFacade.encodeURL(ResponseFacade.java:398)
>
> at org.apache.jsp.Test1_jsp._jspService(Test1_jsp.java:93) at
> org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at
> org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419)
>
> at
> org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
> at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333) at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at
> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
>
> at
> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
>
> at
> org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
>
> at
> org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
>
> at
> org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
> at
> org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
> at
> org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:563)
> at
> org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
>
> at
> org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:399)
> at
> org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:317)
> at
> org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:204)
>
> at
> org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:311)
>
> 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)
>
> In this, the first session gave an error on the second use of the page,
> i.e. the first reload. However, the second session didn't crash until the
> 93rd reload, and the third, until the 49th.
>
> If this a bug, is there any chance of getting it fixed, or of getting a
> circumvention? If I'm doing something bad, please tell me.
>
> Jocelyn Ireson-Paine
> http://www.j-paine.org
> http://www.spreadsheet-parts.org
> +44 (0)7768 534 091
>
> Jocelyn's Cartoons:
> http://www.j-paine.org/blog/jocelyns_cartoons/
>
> On Thu, 9 Jun 2011, Jocelyn Ireson-Paine wrote:
>
> > Hi,
> >
> > I'm getting sporadic null-pointer exceptions from 'response.encodeUrl'.
> > This
> > is with Tomcat 7.0.14, the latest stable version to which I upgraded an
> > hour
> > ago, and Java 1.6.0_26, which again I upgraded to at the same time, under
> > Windows XP. I also got the error under Tomcat 5.5.33, which is why I tried
> > upgrading. I uninstalled old Tomcats and Javas before upgrading.
> >
> > Here's a trace of the error:
> > java.lang.NullPointerException
> > at
> > org.apache.catalina.connector.Response.toAbsolute(Response.java:1594)
> > at
> > org.apache.catalina.connector.Response.encodeURL(Response.java:1198)
> > at
> > org.apache.catalina.connector.ResponseFacade.encodeUrl(ResponseFacade.java:422)
> > at sharesim.ValueGame.encodeUrl(ValueGame.java:468)
> > The fourth line of the trace is my code.
> >
> > To get some diagnostics, I encapsulated 'response.encodeUrl' in the
> > following
> > method, and used 'println' to print to Tomcat's log. This method is the one
> > mentioned on the fourth line of the above trace.
> > private final static String encodeUrl( HttpServletResponse response
> > , String url
> > )
> > {
> > System.out.println( "encodeUrl" );
> > System.out.println( "response=" + response );
> > System.out.println( "url=" + url );
> > String result = null;
> > if ( response == null )
> > result = "not on Web";
> > else
> > result = response.encodeUrl( url );
> > System.out.println( "result=" + result );
> > return result;
> > }
> >
> > As mentioned above, the errors are sporadic. My redirection code gets
> > called
> > on my server when I submit one of my forms. But sometimes, the submit
> > works;
> > sometimes it doesn't. Here are two successive traces from the above method:
> > encodeUrl
> > response=org.apache.catalina.connector.ResponseFacade@1a5ec6c
> > url=/ResearcherValueGame1.jsp
> > result=/ResearcherValueGame1.jsp
> >
> > encodeUrl
> > response=org.apache.catalina.connector.ResponseFacade@1a5ec6c
> > url=/ResearcherValueGame1.jsp
> > The first one worked; the second crashed rather than returning the encoded
> > URL. The URL to be encoded is the same in both cases, and 'response' is
> > evidently the same instance. I don't know how to dump 'response' in order
> > to
> > show relevant fields (whichever they are), but am happy to try it if
> > someone
> > can suggest how.
> >
> > I've found a few mentions on Google of such errors, but nothing definite
> > about it happening in Tomcat 7. One discussion which I thought I'd seen,
> > but
> > can't find again, seemed to suggest that the problem occurred on version 5,
> > possibly because of a missing 'synchronized'. I've not seen anything in
> > recent postings to this list.
> >
> > I wondered whether the problem might be caused by the browser creating
> > malformed cookies, or some such. (I'm using session-handling.) However,
> > this
> > seems unlikely, as the error occurs regardless of whether I use Firefox,
> > Internet Explorer, or Google Chrome.
> >
> > Any ideas?
> >
> > Jocelyn Ireson-Paine
> > http://www.j-paine.org
> >
> > Jocelyn's Cartoons:
> > http://www.j-paine.org/blog/jocelyns_cartoons/
> >
> >
>
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