Processes in UNIX

Question

Hi guys.
I'm trying to execute a process in Compaq UNIX Tru64, but I can't do it!
The code I use is the following:
import java.io.*;
public class RunProcess {
public RunProcess(String[] args) {
if (args.length == 0) {
System.out.println("You missed command");
System.exit(0);
try {
Runtime rt = Runtime.getRuntime();
Process p = rt.exec(args);
int i = Integer.MIN_VALUE;
while ((i = p.waitFor()) != 0) {
System.out.println("waiting...");
System.out.println("Finish" + p.exitValue());
catch (Exception ex) {
ex.printStackTrace();
public static void main(String[] args) {
new RunProcess(args);
If I run this code in Windows, for instance using:
java RunProcess WinWord MyDocument.doc
I've no problem: the MS-Word document appears on my screen and the Java program loop within while until I close the MS-Word document. After that the Java program prints "Finish" and the session in stopped.
If I trying to execute another program (not java!!!!!!) on a UNIX PC using the same RunProcess class, the Java program always loop within while (it continuously prints "waiting...") and it never stops.
Anyone of you could explain such different behaviour from Windows to UNIX?
Thanx.

Answer 1

You should NOT loop in waitFor! It is sufficient to call it only once!
public abstract int waitFor() throws InterruptedException
Waits for the subprocess to complete. This method returns immediately if the subprocess has already terminated. If the subprocess has not yet terminated, the calling thread will be blocked until the subprocess exits.