Can some briefly explain Orion's library/classpath processing?

[Neal Kaiser]

What gets processed first:
$ORION/lib  or $ORION/$WEBAPP/WEB-INF/lib or $ORION/$WEBAPP/WEB-INF/classes
?

I am developing a J2EE app built on the Struts framework and found that my
application would
not work when I put struts.jar in $ORION/$WEBAPP/WEB-INF/lib but would work
when I put struts.jar in
$ORION/lib AND  moved my class files from $ORION/$WEBAPP/WEB-INF/classes to
$ORION/lib.

Can someone explain what was happening there? Is there a rule of thumb of
what dir to use?

Thanks, Neal