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Web Component Certification (OCEJWCD)

Exception: c:catch doubt

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posted 17 years ago

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Hi,

Please see what I am trying to do:

In DD:

In errorPage.jsp

In badPage.jsp:

I was assuming the output as :
Inside the catch
There was an exception java.lang.NullPointerException
Output of errorPage.jsp because of exception caused in line #1

But the output is only containing the output from errorPage.jsp as
divide by zero comes. When I remove the code that caused divide by zero
then only the NPE comes. I see the divide by zero exception supersedes the
NPE.
One more thing: Even if I don't write <%@page errorPage ="errorPage.jsp"%>
in the badPage.jsp, it works for divide by zero exception.

I am using apache-tomcat-5.5.23

Please HELP!

Thanks,

[ June 02, 2007: Message edited by: Chandra Bhatt ]

[ June 02, 2007: Message edited by: Chandra Bhatt ]
[ June 02, 2007: Message edited by: Chandra Bhatt ]

cmbhatt

Niranjan Deshpande

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posted 17 years ago

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<error-page>
<exception-type>java.lang.ArithmeticException</exception-type>
<location>/errorPage.jsp</location>
</error-page>

see the exception type highlighted above..since you are using a ArithmeticException, the errorPage.jsp will be invoked each time a a arithmatic exception ( divide by zero ...in your case) is thrown..

thats why..you are not getting the error page for the null pointer exception..

try using a java.lang.Exception as the exception type...then your errorPage will be a catch all error page

hth

SCJP 1.4 - 95% [ My Story ] - SCWCD 1.4 - 91% [ My Story ]
Performance is a compulsion, not a option, if my existence is to be justified.

Chandra Bhatt

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posted 17 years ago

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Thanks Niranjan,

Still I am not getting why the previous exception message is not
shown on my web page. As in above case, I am only getting the last exception
caused as divide by zero and the exception I caught inside the catch is lost.
I also tried to define the error page for NPE in DD.

Please put some light on this!

Thanks,

cmbhatt

Chandra Bhatt

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posted 17 years ago

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Got It,

Actually the idea didn't come in my head, that the errorPage will be called
dynamically in case exception occurs, so the previous page content will be
superseded by the further page that is called when next exception is
generated.

Note: I didn't write the <%@ page isErrorPage="true"%> on the
top of the errorPage and still it is treated as error page. Can somebody
guide me to understand the issue.

Thanks again!

cmbhatt

Atul Sawant

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posted 17 years ago

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This is because you are declaring errorpage.jsp in Deployment Descriptor as the official error page to be displayed when an Arithmitic exception is thrown.

Mission SCWCD. Mission SCJP Complete: SCJP 1.4 - 91%

Niranjan Deshpande

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posted 17 years ago

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cool....chandra...happy that things worked..

keep doing !

SCJP 1.4 - 95% [ My Story ] - SCWCD 1.4 - 91% [ My Story ]
Performance is a compulsion, not a option, if my existence is to be justified.

Chandra Bhatt

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posted 17 years ago

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Hi Atul,

It means if I define official error page in the DD, and don't add the page
directive <%@ page isErrorPage="true"%> on the errorPage, it will be
treated as errorPage.

It sounds not OK as per it is written in HFSJ page 461 Note: the exception
implicit object is available ONLY to error pages with an explicitly- defined
page directive <%@ page isErrorPage="true"%>

Or I may miss to understand the above note of the HFSJ.

Please confirm!

Thanks Atul for paying attention to this thread!

With Regards,
[ June 03, 2007: Message edited by: Chandra Bhatt ]

cmbhatt

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