multithreading - java thread periodically kills a process -

i have java class kicks off a script via

process proc = runtime.getruntime().exec(" run script"); 

for specific reasons pretty runs time. if script dies whatever reason java class starts up.

now i'm needing kill process every often. decided kick off thread sit , wait specific time, , kill process. java main class, or whatever, still see process die , start up.

i don't know how thread see process , subsequently kill every often. suggestions on how create thread? note, haven't had work threads in little while, i'm little rusty.

simple pseudo code of class basic idea of i'm doing:

class myclass{      process mproc;      main(args){         do{             try{                 mproc = runtime.getruntime().exec("cmd /c myscript");                 mproc.destroy();             } catch(exception e){                 log(e);             }         } while(true); 

i don't know how thread see process , subsequently kill every often.

this not easy of java 6. process class has waitfor() method not take timeout tragic given internally calling wait() -- @ least in unixprocess.

what can do, of hack synchronize on process , call wait(timeoutmillis) yourself. like:

process proc = new processbuilder().command(commandargs).start(); long startmillis = system.currenttimemillis(); synchronized (proc) {     proc.wait(sometimeoutmillis); } long diff = system.currenttimemillis() - startmillis; // if here without being interrupted , delay time more // sometimeoutmillis, process should still running if (diff >= sometimeoutmillis) {    proc.destroy(); } 

the issue there race condition , if process finishes before synchronize on proc going wait ever. solution proc.waitfor() in 1 thread , interrupt in thread once timeout expires.

process proc = new processbuilder().command(commandargs).start(); try {    // interrupted thread    int errorcode = proc.waitfor(); } catch (interruptedexception e) {    // pattern re-interrupt thread    thread.currentthread().interrupt();    // our timeout must have expired need kill process    proc.destroy(); } // maybe stop timeout thread here 

another option use proc.exitvalue() allows test see if process executed. unfortunately instead of returning -1 or throws illegalthreadstateexception if has not finished.