Hi,

>> I don;t know the internals of Tomcat now, but once upon a time, the whole
>> point of Catalina was exactly the above, and not a "Child First
>>Behavior". If
>> CFB is in place in Tomcat, it is because of this bad entropy, and Tomcat
>>is
>> then indirectly adding to it.

>No, it is because the servlet spec defines it (it's a recommendation, not a
>requirement) and Tomcat implements the servlet spec.  No mystery or
>non-standard kludge here.  Maybe Yoav can comment on this for a more
>definitive
>answer?

The Servlet Specification explicitly requires classes from WEB-INF/lib and
WEB-INF/classes be loaded before container classes (and after JDK bootstrap
classes, which includes endorsed extensions).

Due to many requests over several years, Tomcat provides an option for the
user (which may be a server admin of course) to flip the order.  This is
documented in the "delegate" attribute of the "Loader" configuration
element: http://jakarta.apache.org/tomcat/tomcat-5.5-doc/config/loader.html.
A complete explanation with some specific Servlet Spec references is at
http://jakarta.apache.org/tomcat/tomcat-5.5-doc/class-loader-howto.html.

In my experience, this flipping behavior is rarely used.  I am also aware of
at least one other significant container (Orion) that provides this feature,
and in general follows the same classloading model as Tomcat, with all the
relevant implications for log4j.  

Two final comments: every feature and behavior of the classloading tree is
extensively scrutinized both by Tomcat developers and by members of the
Servlet (JSP) Spec expert group(s) before it's implemented in Tomcat.  And
classloader behavior is part of the TCKs (which Tomcat passes 100%).  So
whether anyone feels like it's a bad system or not, it's the standard system
for now and changing it requires going to the Spec/JCP process...

Yoav


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