How I launch an external program and kill the father?

Question

my objective is that a jar file autoupdate himself with other jar file.
I must delete old file and replace with a new one, but it is imposible if it is running.
I think launch auxiliar application to do the work but when I use "Runtime.getRuntime.exec("....")" first program does not finish if the second one is not finished.
Also I tried with "Runtime.getRuntime().exec("cmd /c calc.exe");" and using Threads "setDaemon(true)", but does not work, daemon thread dies when first program finish.
Any idea?
thanks

Answer 1

Hmmm... We've done similar in a VB app... We wrote a "facade" program which looked like the actual product (icons, splash screen, etc) but was in-fact an automatic self-updater.
1. Show splash screen
2. Fetch a "config" file from the server, which tells us the latest version of each component (including the self-updater).
3. If this updater needs updating, download it, exec a batch script and terminate this process... the batch script just renames file updater.new updater.exe and starts updater.exe --> goto step 1.
4. check if the installed product components are up-to-date.
5. download new/updated components and install them.
6. start the actual application.
If I recall, there was no problem with exec'ing a new process and not waiting for it to end in VB... and I'm not getting your problem in java... this launches notepad and the program terminates... be very careful with anything which could write to either standard stream... the child will block when it's output buffer gets full.
class DodgyLauncher
  public static void main(String[] args) {
    new Thread(new Runnable() {
      public void run() {
        try {
          Runtime.getRuntime().exec(new String[] {"cmd", "/c", "notepad.exe", "DodgyLauncher.java"});
        } catch (Exception e) {
          e.printStackTrace();
    }).start();
}Cheers. Keith.