Runtime#exec() from within a J2EE application

Question

I've got a batch processing task running on a timer as part of my J2EE application on WebLogic 8.1 and I'm experiencing problems with invoking Runtime#exec().
To be more accurate, this is what I'm trying to do:
* Moves a file in the filesystem using native shell commands.
* @param src The file to move.
* @param dst The destination file.
public void move(String src, String dst) {
    Runtime runtime = Runtime.getRuntime();
    Process p = runtime.exec(new String[] { "mv", "-f", src, dst });
}Now, this piece of code works perfectly when run manually ("java Move foo.txt bar.txt") but when it's run within the J2EE application -- as the same user as in the manual case -- the file's won't get moved anywhere.
I suppose it's a permission/policy issue. If that's the case, how should I edit the policy file?
I already tried to add the following lines to weblogic.policy:
grant codeBase "file:${user.domain}/myServer/.internal/-" {
  permission java.security.AllPermission;
grant codeBase "file:${user.domain}/myServer/.wlnotdelete/-" {
  permission java.security.AllPermission;
};...but that didn't seem to help at all.

Answer 1

Ok. I managed to solve this one by myself. The solution was to read the "stdout" and "stderr" streams from the process.
Any idea why reading the streams helped?