Inconsistent exit code from Runtime.getRuntime().exec

Question

I'm getting non-deterministic behavior from a call to a native process. Here is the code:
public class Test {
public static void main (String[] pArgs) {
try {
String cmd[] = { "cmp", "-s",
pArgs[0],
pArgs[1] };
System.err.println("running command: ");
Process p = Runtime.getRuntime().exec(cmd);
System.err.println("getting exitcode...");
int exitcode = p.waitFor();
System.err.println(exitcode);
System.err.println(p.exitValue());
} catch(Exception e) {
System.err.println("Caught exception while executing cmd");
e.printStackTrace();
And here is the output:
bock@homeruns[~/work/index]10:08> java Test output output.old
running command:
getting exitcode...
0
0
bock@homeruns[~/work/index]10:08> java Test output output.old
running command:
getting exitcode...
1
1
bock@homeruns[~/work/index]10:08> java Test output output.old
running command:
getting exitcode...
0
0
they should all be 1's because the files are different. when i run it on the command line i get:
bock@homeruns[~/work/index]10:13> cmp -s output output.old ; echo $?
1
any help would definitely be appreciated!
thanks,
roger

Answer 1

thanks for the link. i read through it but it doesn't seem to address why the exit code would be inconsistently reported. the other problems described by that link don't seem to apply to this case because i have not experienced hanging and there is no standard input, standard output, or standard error associated with "cmp -s" - all it does is return the appropriate exit code.
should i be reporting this as a bug to sun? up till recently i've been assuming it was a problem with my code but now i'm not so sure...