Question

I want to run a shell script from within a Java program asynchronously– i.e. after the java program starts execution of that shell script, it carries on with other operations– and does some further work only when the shell script returns a response to it.. i.e. it does not explicitly stop and wait for the shell script’s response.

Is this possible/feasible? How do I implement such functionality?

Basically i will be monitoring multiple servers using a single server that will manage all those servers– for this it will run shell scripts on each of those servers…since there are many servers, and in java its recommended that number of threads not exceed number of cpu cores… hence I need a solution to this problem, that is not dependent on threading (because of threading limitations)…so that I can simultaneously (or near-simultaneously) fire off many such shell scripts without waiting for one of those scripts responses’ (as waiting would affect processing for other shell script commands)… another issue.. the shell commands need to be invoked either on local machine or on remote machines and response is needed from both types of shell script execution(viz local execution and remote execution)…

Answer 1

did you try anything?

you can try something like:

ProcessBuilder builder = new ProcessBuilder("your command to launch script");
Process process = builder.start();

And it does NOT wait by default for the process to complete, so you can execute your code next.

And if you want to do some processing after the process is finished you can try:

int exitVal = process.waitFor();