.exe package uses .jar association, not JRE

Problem: The end-user must have associated .jar files with a JRE in Windows.

If associated with another app e.g. WinZip then the installer will not launch as expected, but instead something else (e.g. WinZip) appears, after the EXE has extracted.

Note, this issue also happens with the PackJacket 0.4.2 installer from http://packjacket.sf.net/download

Fix: Look for the JRE somehow using JAVA_HOME or JRE_HOME environment variables, the registry, something else...?

Steps to reproduce:
cd /d "C:\Program Files\IzPack\sample\simple"
"C:\Program Files\IzPack\bin\compile.bat" install.xml
cd /d "C:\Program Files\IzPack\utils\wrappers\izpack2exe"
izpack2exe.exe --file=..\..\..\sample\simple\install.jar --output=..\..\..\sample\simple\install.exe
start ..\..\..\sample\simple\install.exe

Workaround: change the association manually, before running the installer. I tried to do this - seems it is not so easy.

Relying on the default association of JAR files is a hack IMO. The point of an installer is that we do not know what environment the end user will have.