java - Sending output to external process -

for reason, i'm having problems sending output process i've created in java. external process running in command prompt, , peculiar thing can click that, type, hit enter, , i'll output program. addition program can read output coming program, can't send it.

anyways, here relevant code i'm using isn't working...

try {     processbuilder builder=new processbuilder(args);     builder.redirecterrorstream(true);     final process p=builder.start();     // process has been created , running     try {         string b="";         bufferedreader input = new bufferedreader(new inputstreamreader(p.getinputstream()));         final bufferedwriter output = new bufferedwriter(new outputstreamwriter(p.getoutputstream()));         new thread(){public void run(){             // thread periodically send "get_time" process update on progress             while(true)             {                 try {                     thread.sleep(1000);                     p.exitvalue();                     // p.exitvalue() works when process has ended, normal code goes in catch block                     output.close();                     break;                     // leave infinite loop if program has closed                 } catch (ioexception ex) {                     logger.getlogger(ovmusicui.class.getname()).log(level.severe, null, ex);                     break;                     // leave infinite loop if tried closing our output stream, closed                 } catch (interruptedexception ex) {                     logger.getlogger(ovmusicui.class.getname()).log(level.severe, null, ex);                 } catch (illegalthreadstateexception e) {                     try {                         system.out.println("outputted: get_time");                         output.write("get_time" + system.lineseparator());                         output.flush();                         // give process input                     } catch (ioexception ex) {                         logger.getlogger(ovmusicui.class.getname()).log(level.severe, null, ex);                     }                 }             }         }}.start();         while((b = input.readline()) != null){             system.out.println(new time(system.currenttimemillis()).tostring() + " " + b);             // log output process gives         }         input.close();     } catch (ioexception ex) {         logger.getlogger(ovmusicui.class.getname()).log(level.severe, null, ex);     }     // more code here } catch (ioexception ex) {     logger.getlogger(ovmusicui.class.getname()).log(level.severe, null, ex); } 

if necessary, can give example command , name of external program being run can try yourself...

thanks!

edit: here example of what's passed processbuilder: arrays.aslist("vlc\vlc.exe", "-irc", "-vvv", "http://www.youtube.com/watch?v=xfeys7jfnx8", "--sout", "file/ogg:untitled 1.ogg", "--play-and-exit", "--rc-quiet"). difference use absolute paths instead of relative paths. program vlc media player 2.0.7.

your code has few problems. first, should not use exceptions regular control flow: it's expensive, it's difficult read, , makes handling actual errors more difficult. it's better spawn thread calls p.waitfor() , signals main thread complete, such wait/notify.

also, construction infinite loop , using break instead of return make code more difficult debug; instead, use timer.

it looks output external program working correctly problem reading output. program may buffering own output or may detecting it's not being run interactively , behaving differently.