Today I've been testing and upgrading one of our development servers to Domino 9.0 release. Nowadays is mainly used for XPages development, but it used to deal with Quickr, Sametime, and so on.

I've tried to clean in notes.ini the JavaUserClassesExt variable, that during the years, has been filled with a lot of values not needed any more.

After restarting the server I'm unable to run any XPages application. I always get a 500 Error when invoking an XPage through a URL and in the console I get something like this

03/06/2013 11:24:10 AM  HTTP Web Server: Command Not Handled Exception [/mydb.nsf/mypage.xsp] Anonymous

So the problem seems to affect the whole server.

After having a look at the console I see an error message initializing the XSP Command Manager

Xsp Initialization Error - Could not load class or methods

I stop the HTTP task and in the notes.ini, I restore JavaUserClassesExt to, in some extent, its original values

QPJC1=C:\LOTUS8\DOMINO\quickplace.jar
QPJC2=C:\LOTUS8\DOMINO\log4j-118compat.jar
JavaUserClassesExt=QPJC1,QPJC2

After starting the HTTP task again the XSP Command Manager starts successfully and works again.

For me, a very strange behaviour. What is the relation between Quickr and XPages ?

This problem happened because of manipulating the notes.ini. For more common problems you can a look here to more common solutions.