How to locate files in cache

Question

I'm using JDK 6.11 on MS Windows and would like to call Runtime.getRuntime().exec() on a JWS downloaded .exe file. Therefore I need the exact path to the file in the JWS cache. I could do a file search in
C:\\Dokumente und Einstellungen\\Stefan von Wachter\\Anwendungsdaten\\Sun\\Java\\Deployment\\cache
but this seems to be an error prone solution. (Although it works on my system.)
It is interesting that I can successfully call loadLibrary() for a .dll residing in the same .jar archive than the .exe .
I don't understand why there isn't an API in javax.jnlp.DownloadService for getting the location of the downloaded files.
There is a JNLP sample WebPad, but it doesn't show my problem because the source code for HelpSet is not available.
There is a related forum thread
http://forums.sun.com/thread.jspa?threadID=5319615&tstart=150
(Problem with java web start resources (no !/ in spec) )
but it doesn't contain a clean solution.
Thanks for help,
Stefan

Answer 1

My installer app is now running, but not working ...
It should be mentioned that the installer.jnlp needs a security statement for accessing files on local disk:
  <security>
    <all-permissions/>
  </security> Unfortunately I still don't see how to get a (.exe or other) file out from the .jar and copy it to a specified location on the local disk.
It ist possible to read an image file using:
         URL icURL = getClass().getResource( "/winexeinstaller/TMLogo2.png" );
         ImageIcon myIc = new javax.swing.ImageIcon( icURL );But if I call
      FileInputStream   from = new FileInputStream( fromFile );it throws the FileNotFoundException
SCHWERWIEGEND: fileCopy failed
java.io.FileNotFoundException: http:\10.64.76.247\apixWithOcean\lib\WinExeInstaller.jar!\winexeinstaller\DataTransfer.zip (Die Syntax für den Dateinamen, Verzeichnisnamen oder die Datenträgerbezeichnung ist falsch)
     at java.io.FileInputStream.open(Native Method)
     at java.io.FileInputStream.<init>(Unknown Source)
     at winexeinstaller.Installer.fileCopy(Installer.java:174)
     at winexeinstaller.Installer.<init>(Installer.java:72)
     at winexeinstaller.Installer.main(Installer.java:96)These problems have been discussed here, but I don't see the solution.
The jws Spec says:
The installer extension is intended to install platform-specific native code that requires a more complicated
setup than simply loading a native library into the JVM, such as installing a JRE or device driver. The installer
executed by the JNLP Client must be a Java Technology-based application. Note that this does not limit the
kind of code that can be installed or executed. For example, the installer could be a thin wrapper that executes
a traditional native installer, executes a shell script, or unzips a ZIP file with native code onto the disk.So it should be possible. Could somebody tell my how?
Thanks,
Stefan