Start shell script in background from java program

Question

I currently start a shell script from my Java by code looking like this:

ProcessBuilder processBuilder = new ProcessBuilder();
processBuilder.directory("/directory/where/the/script/is/located/");
String[] command = new String[]{"sh", "myScript.sh"};
processBuilder.command(command);
Map<String, String> env = processBuilder.environment();
//tweak the environment with needed additions
env.put(...);
Process p = processBuilder.start();

stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
stdError = new BufferedReader(new InputStreamReader(p.getErrorStream()));

// read the output from the command
String line;
while ((line = stdInput.readLine()) != null)
{
  logger.fine(line);
}
p.waitFor();
int returnCode = p.exitValue();
// Return something according to the return code
return ...;

If I now want to start the script and not wait for it to end (and thus losing the ability to return according to return code), but still with being able to tweak the environment beforehand? how should I proceed?

Thank you

Not waiting for it to end also means that you lose ability to get the output from the process, right? — Nivas
– Nivas, Commented Sep 13, 2011 at 10:02
@Nivas not if it is started in a different thread, then both stdout and stderr from the process can (and must) be captured — Miserable Variable
– Miserable Variable, Commented Sep 13, 2011 at 10:20

Suraj Chandran · Accepted Answer · 2011-09-13 10:02:08Z

5

Just do the entire thing in a new thread.

Wrap the entire above code in a Runnable and start a Thread for it. Your main code can continue doing something else. In the runnable once you get the result from the child process use some notify(or observer pattern) to notify interested parties.

answered Sep 13, 2011 at 10:02

Suraj Chandran

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