                    Apache Tomcat Version 4.0.6
                    ===========================
                            Release Notes
                            =============

$Id: RELEASE-NOTES-4.0.6.txt,v 1.1.2.1 2002/10/08 13:34:54 remm Exp $


============
INTRODUCTION:
============


This document describes the changes that have been made in the current
release candidate release of Apache Tomcat, relative to the previous release.
The release notes for all prior releases of Tomcat 4.0 are also included, for
your reference.

Bug reports should be entered at the bug reporting system for
Jakarta projects at:

        http://nagoya.apache.org/bugzilla/

Please report bugs and feature requests under product name "Tomcat 4".



============
NEW FEATURES:
============


--------------------
General New Features:
--------------------

     ***** Please note the revised documentation below related to *****
     ***** using XML parsers with Tomcat 4.0 based applications.  *****

[F]  Coyote:
     Upgrade to latest version.



---------------------
Catalina New Features:
---------------------



-------------------
Jasper New Features:
-------------------



--------------------
Webapps New Features:
--------------------



==========================
BUG FIXES AND IMPROVEMENTS:
==========================


------------------
Generic Bug Fixes:
------------------


------------------
Catalina Bug Fixes:
------------------

[F]  InvokerServlet:
     Improve class filter to prevent invocation of internal Catalina servlets.


----------------
Jasper Bug Fixes:
----------------



-----------------
Webapps Bug Fixes:
-----------------



----------------------
Bugzilla Bugs Resolved:
----------------------



============================
KNOWN ISSUES IN THIS RELEASE:
============================

* Tomcat 4.0 and JNI Based Applications
* Tomcat 4.0 Standard APIs Available
* Tomcat 4.0 and XML Parsers
* Web application reloading and static fields in shared libraries
* JAVAC leaking memory
* Linux and Sun JDK 1.2.x - 1.3.x
* Jasper and Jikes
* Tomcat 4.0 and Apache Cocoon 2.0
* Enabling SSI and CGI Support
* Tomcat 4.0 and Sun JDK 1.4 beta 3


-------------------------------------
Tomcat 4.0 and JNI Based Applications:
-------------------------------------

Applications that require native libraries must ensure that the libraries have
been loaded prior to use.  Typically, this is done with a call like:

  static {
    System.loadLibrary("path-to-library-file");
  }

in some class.  However, the application must also ensure that the library is
not loaded more than once.  If the above code were placed in a class inside
the web application (i.e. under /WEB-INF/classes or /WEB-INF/lib), and the
application were reloaded, the loadLibrary() call would be attempted a second
time.

To avoid this problem, place classes that load native libraries outside of the
web application, and ensure that the loadLibrary() call is executed only once
during the lifetime of a particular JVM.


----------------------------------
Tomcat 4.0 Standard APIs Available:
----------------------------------

A standard installation of Tomcat 4 makes all of the following APIs available
for use by web applications (by placing them in "common/lib" or "lib"):
* activation.jar (Java Activation Framework)
* jdbc2_0-stdext.jar (JDBC 2.0 Optional Package, javax.sql.*)
* jndi.jar (JNDI 1.2 base API classes)
* jta-spec1_0_1 (Java Transacation APIs)
* mail.jar (JavaMail 1.2)
* servlet.jar (Servlet 2.3 and JSP 1.2 APIs)
* tyrex-0.9.7.0.jar (Tyrex XA-compatible data source from tyrex.exolab.org)
* xerces.jar (Xerces 1.4.3)

You can make additional APIs available to all of your web applications by
putting unpacked classes into a "classes" directory (not created by default),
or by placing them in JAR files in the "lib" directory.


--------------------------
Tomcat 4.0 and XML Parsers:
--------------------------

As described above, Tomcat 4.0 makes an XML parser (and many other standard
APIs) available to web applications.  This parser is also used internally
to parse web.xml files and the server.xml configuration file.  If you wish,
you may replace the "xerces.jar" file in "common/lib" with another XML parser,
as long as it is compatible with the JAXP/1.1 APIs.


---------------------------------------------------------------
Web application reloading and static fields in shared libraries:
---------------------------------------------------------------

Some shared libraries (many are part of the JDK) keep references to objects
instantiated by the web application. To avoid class loading related problems
(ClassCastExceptions, messages indicating that the classloader 
is stopped, ...), the shared libraries state should be reinitialized.

Something which could help is to avoid putting classes which would be 
referenced by a shared static field in the web application classloader, 
and put them in the shared classloader instead (the JARs should be put in the 
"lib" folder, and classes should be put in the "classes" folder).


--------------------
JAVAC leaking memory:
--------------------

The Java compiler leaks memory each time a class is compiled. Web applications
containing hundreds of JSP files may as a result trigger out of memory errors 
once a significant number of pages have been accessed. The memory can only be 
freed by stopping Tomcat and then restarting it.

The JSP command line compiler (JSPC) can also be used to precompile the JSPs.


-------------------------------
Linux and Sun JDK 1.2.x - 1.3.x:
-------------------------------

Virtual machine crashes can be experienced when using certain combinations of
kernel / glibc under Linux with Sun Hotspot 1.2 to 1.3. The crashes were 
reported to occur mostly on startup. Sun JDK 1.4 does not exhibit the problems,
and neither does IBM JDK for Linux.

The problems can be fixed by reducing the default stack size. At bash shell, 
do "ulimit -s 2048"; use "limit stacksize 2048" for tcsh.

GLIBC 2.2 / Linux 2.4 users should also define an environment variable:
export LD_ASSUME_KERNEL=2.2.5


----------------
Jasper and Jikes:
----------------

Jikes can be used with the Jasper JSP page compiler, but the runtime classes 
JAR of the JDK or JRE (depending on what is installed on the computer) must
be added to the system classpath.

This can be achieved by editing the main catalina script, and adding the rt.jar
file:

On Windows:
  line 71 of %CATALINA_HOME%\bin\catalina.bat, change
set CP=%CATALINA_HOME%\bin\bootstrap.jar;%JAVA_HOME%\lib\tools.jar
  to
set CP=%JAVA_HOME%\jre\lib\rt.jar;%CATALINA_HOME%\bin\bootstrap.jar;%JAVA_HOME%\lib\tools.jar

On Unix or Unix-like OSes:
  line 89 of $CATALINA_HOME/bin/catalina.sh, change
CP="$CATALINA_HOME/bin/bootstrap.jar"
  to
CP="$JAVA_HOME/jre/lib/rt.jar:$CATALINA_HOME/bin/bootstrap.jar"


--------------------------------
Tomcat 4.0 and Apache Cocoon 2.0:
--------------------------------

For optimal performance with Apache Cocoon 2.0, it is recommended to use the
HTTP/1.0 connector.


----------------------------
Enabling SSI and CGI Support:
----------------------------

Having CGI and SSI available to web applications created security problems when
using a security manager (as a malicious web application could use them to 
sidestep the security manager access control). In Tomcat 4.0, they have been
disabled by default, as our goal is to provide a fully secure default 
configuration. However, CGI and SSI remain available.

On Windows:
* rename the file %CATALINA_HOME%\server\lib\servlets-cgi.renametojar to
  %CATALINA_HOME%\server\lib\servlets-cgi.jar.
* rename the file %CATALINA_HOME%\server\lib\servlets-ssi.renametojar to
  %CATALINA_HOME%\server\lib\servlets-ssi.jar.
* in %CATALINA_HOME%\conf\web.xml, uncomment the servlet declarations starting
  line 165 and 213, as well as the associated servlet mappings 
  line 265 and 274. Alternately, these servlet declarations and mappings can
  be added to your web application deployment descriptor.

On Unix:
* rename the file $CATALINA_HOME/server/lib/servlets-cgi.renametojar to
  $CATALINA_HOME/server/lib/servlets-cgi.jar.
* rename the file $CATALINA_HOME/server/lib/servlets-ssi.renametojar to
  $CATALINA_HOME/server/lib/servlets-ssi.jar.
* in $CATALINA_HOME/conf/web.xml, uncomment the servlet declarations starting
  line 165 and 213, as well as the associated servlet mappings 
  line 265 and 274. Alternately, these servlet declarations and mappings can
  be added to your web application deployment descriptor.


---------------------------------
Tomcat 4.0 and Sun JDK 1.4 beta 3:
---------------------------------

Some unpredictable classloading behavior has been reported when Tomcat is 
used with Sun JDK 1.4 beta 3. The problem has been fixed with Sun JDK 1.4 
Realease Candidate or later.




