Problem from Difference betw Thread and Process.

Question

Hi,
my app create new Process and execute subtask. So, Main Process wait for the sub process to finish. Like follow.
Process child= Runtime.getRuntime().exec(cmds);//run java ClassName cmdArrays..
try {
child.waitFor();
} catch (InterruptedException e) {
//when error ocurrs it return error message
return "Running Process error :\n "+
e.getMessage();
In this case if sub process run swing application, parent process seem to freeze.
It will wait forever.
I try to create new Thread to create new Process. But, the problem is child process is created by parent process. But, Parent is Thread not process.
So, waitFor still make parent process freeze. Is this right?
How can I solve this problem?

Answer 1

waitFor() becasue I need input/errorStream You do not need to call waitFor() first in order to get the input/error streams of the child process!
                        Runtime         rt=Runtime.getRuntime();
                        Process         proc=rt.exec(command);
                        InputStream is=proc.getInputStream();
                        LineNumberReader lnr=new LineNumberReader(new InputStreamReader (is));
                        sRet=lnr.readLine();
                        String line;
                        while((line=lnr.readLine()) != null) {
                                if (DEBUG1) System.out.println(line);
                                InputStream is2=proc.getErrorStream();
                                LineNumberReader lnr2=new LineNumberReader(new InputStreamReader (is2));
                                while((line=lnr2.readLine()) != null) {
                                        System.err.println(line);
                        iRet=proc.waitFor();