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Posted to users@wicket.apache.org by Rafael Barrera Oro <bo...@gmail.com> on 2013/11/07 04:33:00 UTC

Bizarre undentified error resulting in blank page

Hello!

I've stumbled across a tricky one, i am getting a blank screen withouth any
error in the logs, the only thing i can observe is the following javascript
error on the js console:

*Uncaught TypeError: Cannot call method 'appendChild' of
null wicket-ajax-debug.js:207*

*GET http://localhost:8080/lars/app/src/debug.js
<http://www.google.com/url?q=http%3A%2F%2Flocalhost%3A8080%2Flars%2Fapp%2Fsrc%2Fdebug.js&sa=D&sntz=1&usg=AFQjCNFTx3mceKhWiXKl1lTEwHaeEdOAyQ>
404
(Not Found)*

This only happens if "development" mode is set in the web.xml of the
project (the js error happens because document.body is null).

I still don't know if this the cause or a consequence of whatever is going
wrong.

The really weird thing is the error does not happen if i comment certain
lines of code within a class all pages in the project inherit from, these
lines invoke some getters for attributes of the page, set a few
pageParameters properties and retrieve the session to do stuff. For
example, there is a line that is quite like the following:

PageParameters pageParameters = getBean().getParameters();

To my amazement, if i comment it out and replace it for, lets say...

PageParameters pageParameters = new PageParameters();

everything goes smoothly...

Has anyone ran across something similar?

Thanks in advance!
Rafael

Re: Bizarre undentified error resulting in blank page

Posted by Peter Henderson <pe...@starjar.com>.
Hi,

Just a though.
Could it be the constructor of the base class calling abstract methods,
before the child instance has been initialized fully? I've done that a
couple of times and it produces some very weird results.

Peter.





On 7 November 2013 03:33, Rafael Barrera Oro <bo...@gmail.com> wrote:

> Hello!
>
> I've stumbled across a tricky one, i am getting a blank screen withouth any
> error in the logs, the only thing i can observe is the following javascript
> error on the js console:
>
> *Uncaught TypeError: Cannot call method 'appendChild' of
> null wicket-ajax-debug.js:207*
>
> *GET http://localhost:8080/lars/app/src/debug.js
> <
> http://www.google.com/url?q=http%3A%2F%2Flocalhost%3A8080%2Flars%2Fapp%2Fsrc%2Fdebug.js&sa=D&sntz=1&usg=AFQjCNFTx3mceKhWiXKl1lTEwHaeEdOAyQ
> >
> 404
> (Not Found)*
>
> This only happens if "development" mode is set in the web.xml of the
> project (the js error happens because document.body is null).
>
> I still don't know if this the cause or a consequence of whatever is going
> wrong.
>
> The really weird thing is the error does not happen if i comment certain
> lines of code within a class all pages in the project inherit from, these
> lines invoke some getters for attributes of the page, set a few
> pageParameters properties and retrieve the session to do stuff. For
> example, there is a line that is quite like the following:
>
> PageParameters pageParameters = getBean().getParameters();
>
> To my amazement, if i comment it out and replace it for, lets say...
>
> PageParameters pageParameters = new PageParameters();
>
> everything goes smoothly...
>
> Has anyone ran across something similar?
>
> Thanks in advance!
> Rafael
>



-- 
Peter Henderson

Director
Starjar Ltd.
0330 088 1662
www.starjar.com

Re: Bizarre undentified error resulting in blank page

Posted by Martin Grigorov <mg...@apache.org>.
Hi,


On Thu, Nov 7, 2013 at 5:33 AM, Rafael Barrera Oro <bo...@gmail.com>wrote:

> Hello!
>
> I've stumbled across a tricky one, i am getting a blank screen withouth any
> error in the logs, the only thing i can observe is the following javascript
> error on the js console:
>
> *Uncaught TypeError: Cannot call method 'appendChild' of
> null wicket-ajax-debug.js:207*
>
> *GET http://localhost:8080/lars/app/src/debug.js
> <
> http://www.google.com/url?q=http%3A%2F%2Flocalhost%3A8080%2Flars%2Fapp%2Fsrc%2Fdebug.js&sa=D&sntz=1&usg=AFQjCNFTx3mceKhWiXKl1lTEwHaeEdOAyQ
> >
> 404
> (Not Found)*
>
> This only happens if "development" mode is set in the web.xml of the
> project (the js error happens because document.body is null).
>

This is strange indeed.


>
> I still don't know if this the cause or a consequence of whatever is going
> wrong.
>
> The really weird thing is the error does not happen if i comment certain
> lines of code within a class all pages in the project inherit from, these
> lines invoke some getters for attributes of the page, set a few
> pageParameters properties and retrieve the session to do stuff. For
> example, there is a line that is quite like the following:
>
> PageParameters pageParameters = getBean().getParameters();
>

what are the keys/values in these problematic parameters ?


>
> To my amazement, if i comment it out and replace it for, lets say...
>
> PageParameters pageParameters = new PageParameters();
>
> everything goes smoothly...
>
> Has anyone ran across something similar?
>
> Thanks in advance!
> Rafael