Run a external application in java but don't wait for it to finish

java process termination
Daniel Cisek picture Daniel Cisek · Mar 8, 2012 · Viewed 7k times · Source

I'm writing an app in java allowing me to run other applications. To do that, I've used an Process class object, but when I do, the app awaits the process to end before exiting itself. Is there a way to run external application in Java, but don't wait for it to finish?

public static void main(String[] args)
{
FastAppManager appManager = new FastAppManager();
appManager.startFastApp("notepad");
}

public void startFastApp(String name) throws IOException
{
    Process process = new ProcessBuilder(name).start(); 
}

Answer

Esben Skov Pedersen picture Esben Skov Pedersen · Mar 8, 2012

ProcessBuilder.start() does not wait for process to finish. You need to call Process.waitFor() to get that behaviour.

I did a small test with this program

public static void main(String[] args) throws IOException, InterruptedException {
    new ProcessBuilder("notepad").start();
}

When run in netbeans it appear to be still running. When running from command line with java -jar it returns immediately.

So your program is probably not waiting to exit, but your IDE makes it seem so.

Related questions

How do I trim a file extension from a String in Java?

What's the most efficient way to trim the suffix in Java, like this: title part1.txt title part2.html => title part1 title part2

Read More
How to get a list of current open windows/process with Java?

Does any one know how do I get the current open windows or process of a local machine using Java? What I'm trying to do is: list the current open task, windows or process open, like in Windows Taskmanager, but …

Read More
Killing a process using Java

I would like to know how to "kill" a process that has started up. I am aware of the Process API, but I am not sure, If I can use that to "kill" an already running process, such as firefox.…

Read More