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While trying out some error-handling on JSP I noticed some strange behaviour.

  • I create a Myobject but don't put anything in it to cause a nullpointer for testing.

  • I have included the errorPage directive in my page so it should go to my errorpage when this exception occurs.

The actual error will occur in the input of a form:

....
 <input type="hidden" id="INITIAL_ACTION" name="INITIAL_ACTION" value="<%=Myobject.myMethod()%>"/>
<input type="hidden" name="INITIAL_PAGE" ....

I see the content of my errorpage so the errorpage directive is working but the page doesn't look normal. Now when i look at the source of the page, it looks like the errorpage is actualy inserted into the value of this INITIAL_ACTION input on my previous page instead of being a forward:

...
        <input id="INITIAL_ACTION" type="hidden" value=" <html> <head> <title>ErrorPage</title> <link rel = 'stylesheet' type = 'text/css' href = '../css/newstyle.css' /> </head> <body> <div id=" name="INITIAL_ACTION"></input>
        <table class="borderedtable">

            <tbody>
                <tr> … </tr>
                <tr> … </tr>
    ...

Of course this is giving me some layout/css issues on the actual error-page. Could anyone please explain this behaviour or point me in the right direction?

Edit :

Increasing the page buffer works.

But this would be hard for my current application to identify which pages need this to make sure their error-handling works.

The problem was that the first double quoute of the id-attribute of the first DIV in the error page was used to close the value-attribute of the place where it was inserted..

at the top of the errorpage I have added a html-comment which contains a double quote + explanation.. Now that quote is used and the rest of the page is rendered fine.

But I don't realy like my solution, doesn't feel solid

gotjee
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  • I'm not sure why you think that, but Myobject = null, so it's just a nullpointer call I have created to get an error. But the problem was indeed that it's a very large JSP with the default 8kb buffer. so once it goes over that & in the remaining part there occurs an error, the server will include the errorpage rather then forward like Mark Thomas replied. In the end I moved the error-page to the web.xml errorpage attribute and removed the directive on the jsp. But than neither the forward or include happend on large pages. So I did increase my buffer on those large jsp's. – gotjee Mar 18 '14 at 23:33

1 Answers1

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I'm guessing that you are using Apache Tomcat or one of the other JSP containers that uses Jasper (Tomcat's JSP engine) or a derivative of it.

If the response has already been committed when an error occurs, Jasper includes the error page rather than forwarding to it as that is the best it can do given the circumstances.

To forward to the error page you'll need to perform the action that triggers the error before the response is committed. Possible ways to do this include:

  • Increase the size of the page buffer so the response is committed later
  • Refactor the page so the code that triggers the error is executed earlier
Mark Thomas
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  • Thanks for your feedback, I'm using weblogic, increasing the buffer does solve the problem for that page, But it means I should identify all possible pages where this can occur which is not easy. the main problem why the errorpage looked bad when included is because it used the doublequote " from the first div inside the errorpage was suddenly used to close the value-attribute of the input. because of the the div didn't exist and the layout didn't trigger. in my error page I have now added
    somewhere at the top. now the page looks OK     – gotjee Mar 17 '14 at 14:52
  • Ok the dummy div is not needed. adding a double quote inside a html comment at the top of the included errorpage solves the problem for me. – gotjee Mar 17 '14 at 15:12