Why don’t you start the executable using QProcess? This gives you an asynchronous for free.

But if you want to run with another cmd.exe why don’t you use your main as a wrapper for the java process and then use QProcess to start such main?

I wonder If can run that in a separate shell?

What can I search for, when I want to use the wrapper possibility?

First:
Don’t use backslashes for the program path, use forward slashes. Qt will do the translation transparently.

Second:
Why do you want to involve a shell? It will do nothing else than calling java.exe with your arguments! Does the code you presented not work?

The code in my first post works, I can invoke my extarnal.jar from my Qt-Project.

But my external.jar continuously listens on the socket to a port, while the expected message is never being sent by my suspended Qt-Project.

Therefore I try to make run the external.jar indipendent.

I meant the second snippet, using QProcess. Does that work?

According to the TaskManager a java.exe appears just for 1-2 seconds and disappears, but the jar is not executed properly.

And it does work from the command line itself? How about giving a complete path to your module.db – it’s very likely that it is not found by your java application.

Yes, when I call “java -jar external.jar -m modules.db … “ it works.

I have catched in external.jar already if that modules.db file would not exist, it would throw an FileNotFound-Exception; but I’ll try it.

Here I call another *.jar, Its a Server, which listens uninterrupted to a socket and prints status messages System.out.println(“Bla”) continously as well. This jar has an infinte while-loop and does not terminate..
SO when I start this, another cmd.exe opens and that output should be visible?

Each start() my pid() is changed, visible on my Parent command line window, but no other cmd.exe opens for this Process.

When p_ToObject (the parent) is deleted, my process is terminated as well, right?

Why do you expect a cmd.exe running in case you start a java.exe?

These *.jars have System.out.println(“kljdas”); so without any further cmd.exe nothing is visible?

Then the only way I recognize the running jar is the java.exe in the TaskManager?

And since the jar is running continuously, I would say my java.exe should not disappear?

Your java.exe does not “disappear”. It has no user interface, so it runs in the background, where it belongs.

If you want to see the output of stdout or stderr, you should write a .bat file. Either this opens a cmd.exe automatically when run, or you have to give it as argument to cmd.exe.

Better yet: if you want to display the output, why not make your Qt application display it instead in some nicely integrated way? QProcess gives you access to the stdout and stderr outputs of the process, after all.

To start in a separate shell try to detach the Process. Then you have your own cmd.exe:

hth!