When MySQL stops responding or is not running, my Joomla site displays this error:
Error displaying the error page: Application Instantiation Error
I need to change this description.
Which file can I find this so I can edit it?
1 Answer
As you've already pointed out, the error is in two parts and because it happens so early in the application startup cycle even the JErrorPage class fails.
Normally Joomla would use language files that use a key/value structure and you could then add an override via Extensions-> Language Manager-> Language Overrides but it looks like they aren't even loaded at this point.
So, the error is assembled for two locations, first the actual error when JFactory is asked for the current application instance in JFactory::getApplication(). The odd thing about the error is I'm not clear on how this relates to MySQL going away, usually that is handled much better. This is the one you've found in /libraries/joomla/factory.php
The other part of the error message is prepended when the JErrorPage class tries to handle the exception thrown by JFactory::getApplication() this is found in /libraries/cms/error/page.php.
Both of these are core files and shouldn't be modified for obvious reasons. The other reason is that as Joomla releases security updates or feature upgrades your changes could be overwritten anyway. Personally I would be focusing on fixing the database issue.
