Eclipse Java Execution Environment Description Files

At work I'm working on a java project that needs some command line arguments passed to the JRE to work correctly (maximum allowed memory, etc.).

I have these set in the Installed JREs section in Eclipse's preferences which is all good. However, it gets real frustrating because whenever I upgrade my JDK these get lost. This is because the JDK I had is no longer there an is automatically removed by eclipse, and the new one is detected and added without any customizations.

So I tried to tell my project to use an "Execution Environment" instead of a specific JRE. However eclipse (3.4) doesn't let you modify it's list of execution enviroments (or customize the command line arguments). You can, however, define a new JRE using an Execution Environment Description file.

It was hard to find documentation about this so called .ee file. I found just one page that described the possible settings that can be put in the file, with a short description, but I had to reverse engineer the values for these settings.

Finally I came up with this, which actually works:

## Execution Environment description file for MyProject
-Dee.name=MyProject_EE
-Djava.home=${ee.home}/jre
-Dee.executable=${ee.home}/jre/bin/java
-Dee.executable.console=${ee.home}/jre/bin/java
-Dee.bootclasspath=${ee.home}/jre/lib/resources.jar:${ee.home}/jre/lib/rt.jar:${ee.home}/jre/lib/jsse.jar:${ee.home}/jre/lib/jce.jar:${ee.hom$
-Dee.language.level=1.6
-Dee.library.path=${ee.home}/jre/lib/i386:${ee.home}/jre/lib/i386/server
-Dee.src=${ee.home}/src.zip
-Dee.javadoc.http://java.sun.com/javase/6/docs/api/index.html
-Dee.ext.dirs=${ee.home}/jre/lib/ext
-Dee.vm.library=${ee.home}/jre/lib/i386/server/libjvm.so
-server
-Xmx768m
-XX:MaxNewSize=384m
-XX:MaxPermSize=144m
-XX:+UseConcMarkSweepGC
-XX:+CMSClassUnloadingEnabled
-Dcom.sun.management.jmxremote=true
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false

Notice the ${ee.home} in the paths. It seems that this is the only variable that can be used in the ee file. It get's replaced with the path to the ee file, so for this to work the ee file must be placed in the JDK's base directory.
The reason I'm using this variable instead of absolute paths is that on the next JDK upgrade I'll just need to copy the file to the new JDK's directory and it will continue working (soft linking the jdk directory doesn't work - eclipse follows the links and creates a broken JRE).
Of course you could generate a new ee file for each JDK version.

I also created another variant of this ee file with JIP command line arguments, so I have two JREs defined. This way when ever I want to profile my project, I don't need to create a special runtime configuration, but just choose a the other JRE. To make things even easier, I have two Server (tomcat) definitions, one with each JRE. Starting tomcat with JIP is just a matter of starting the second server instead of the first. Pretty nifty.
BTW, the extra setting for JIP is:

-javaagent:/usr/local/jip-1.1.1/profile/profile.jar -Dprofile.properties=/var/proj/MyProject/webapp.profile.properties

P.S.: It would be great to see this file coming from the upstream package. Maybe sun can include it in their JDK distrubtion, or maybe it could be added to gentoo's package (possibly with an eclipse/OSGi use flag?)