Hi Jim,
the purpose of waitFor() method as you can see form java documentation
http://java.sun.com/javase/6/docs/api/java/lang/Process.html#waitFor()
is to block the current process untill the program you opened terminates
so if you try this block of code
try {
proc = rt.exec("regedit");
proc.waitFor();
proc = rt.exec("calc");
} catch (Exception e) {
System.out.println("regedit is an unknown command.");
}
the calculator program won't start untill you close the "regedit"
but if you removed the waitFor() method the two programs will start together
Hope I Helped
On 1/22/09, Jim <[email protected]> wrote:
>
> Hi,
>
> I have a question about one of the examples in the lesson "Tour of
> java.lang.* and java.util.* classes". The example is about the
> Process and Runtime classes. Here is the example program:
>
> 1 class RuntimeDemo {
> 2 public static void main(String args[]) {
> 3 Runtime rt = Runtime.getRuntime();
> 4 Process proc;
> 5 try {
> 6 proc = rt.exec("regedit");
> 7 proc.waitFor(); //try removing this line
> 8 } catch (Exception e) {
> 9 System.out.println("regedit is an unknown
> 10 command.");
> 11 }
> 12 }
> 13 }
>
> When I ran the program, the Registry Editor appeared. i tried running
> the program with and without the proc.waitFor() line, and did not
> notice any difference between the programs. In both cases, the
> Registry Editor appeared, and when I closed the editor, the program
> stopped.
>
> What should the different behaviors be for the two programs? I use
> NetBeans 6.5. Thank you!
>
> Jim Tarsi
> >
>
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