Same exception different handle in tomcat4.1 and weblogic6.1

Wrox Book "Professional SCWCD Certification" said:
In a similar manner, the snippet given below will forward any ServletException or any subclass of
ServletException thrown by a servlet to the JSP page at location /error/error.jsp:
<error-page>
<exception-type>javax.servlet.ServletException</exception-type>
<location>/error/error.jsp</location>
</error-page>
My test.jsp:
<%@ page contentType="text/html; charset=GBK" %>
<html>
<head>
<title>
test
</title>
</head>
<body>
<h1>
<%
int random=(int)(5*Math.random());
//int random=0;
System.out.println("random="+random);
switch(random){
case 0 :{
System.out.println("case 0");
throw new java.io.IOException("mellon io excpeiton ");
}
case 1 : {
System.out.println("case 1");
throw new java.sql.SQLException("mellon sql exception ");
}
case 2 : {
System.out.println("case 2");
throw new java.sql.SQLWarning("mellon sql warning ");
}
case 3 : {
System.out.println("case 3");
throw new scwcd.exception.SubOfServletException("mellon SubOfServletException ");
}
case 4 : {
System.out.println("case 4");
throw new javax.servlet.ServletException("mellon ServletException ");
}
}
%>
</h1>
</body>
</html>
My web.xml:
<web-app>
<servlet>
<servlet-name>servlet1</servlet-name>
<servlet-class>scwcd.Servlet1</servlet-class>
</servlet>
<error-page>
<exception-type>java.io.IOException</exception-type>
<location>/errorpage/IOExceptionError.jsp</location>
</error-page>
<error-page>
<exception-type>java.sql.SQLException</exception-type>
<location>/errorpage/SQLExceptionError.jsp</location>
</error-page>
<error-page>
<exception-type>java.sql.SQLWarning</exception-type>
<location>/errorpage/SQLWarningError.jsp</location>
</error-page>
<error-page>
<exception-type>javax.servlet.ServletException</exception-type>
<location>/errorpage/ServletExceptionError.jsp</location>
</error-page>
<error-page>
<exception-type>scwcd.exception.SubOfServletException</exception-type>
<location>/errorpage/SubOfServletExceptionError.jsp</location>
</error-page>
</web-app>
Of course I have five different error pages as expected.
In tomcat4.1 when the random is 1 and 2 ,
tomcat dispatch the exception to ServletExceptionError.jsp.
When the random is 0 ,tomcat dispatch the exception to
IOExceptionError.jsp.
When the random is 3 ,tomcat dispatch the exception to
SubOfServletExceptionError.jsp.
When the random is 4,tomcat dispatch the exception to
ServletExceptionError.jsp.
I refreshed the test.jsp many many times but tomcat never dispatch the exception
to SQLWarningError.jsp or SQLExceptionError.jsp.
I test them in weblogic6.1 and get the different result:
When the random is 0 ,weblogic dispatch the exception to
IOExceptionError.jsp.
When the random is 1 ,weblogic dispatch the exception to
SQLExceptionError.jsp.
When the random is 2 ,weblogic dispatch the exception to
SQLWarningError.jsp.
When the random is 3 and 4,weblogic dispatch the exception to
ServletExceptionError.jsp.
The weblogic's result fits the book says well but tomcat's does not.
Which one should I trust in the exam?
[ February 27, 2003: Message edited by: sun mellon ]

Just curious - how does weblogic handle the exceptions coming from servlets vs exceptions coming from Jsp pages, same as tomcat?
Thx,
Calina

And btw, we need to stick with the specs for the exam, not particular implementations of jsp containers.