View Full Version : Java: Process output in System.out

October 20th, 2005, 08:00 PM

I start processes in a Java application. How can I get the output of those to the Java System console?

Process p = Runtime.getRuntime().exec("program");


I guess they are the responsible methods - how to get them on System.out or System.err

October 20th, 2005, 08:22 PM
How about something like this:

try {

// start up the command in child process
String cmd = "/bin/ls -lrt";
Process child = Runtime.getRuntime().exec(cmd);

// hook up child process output to parent
InputStream lsOut = child.getInputStream();
InputStreamReader r = new InputStreamReader(lsOut);
BufferedReader in = new BufferedReader(r);

// read the child process' output
String line;
while ((line = in.readLine()) != null)

} catch (Exception e) { // exception thrown

System.out.println("Command failed!");


October 20th, 2005, 11:04 PM
This works really fine - thanks.

I just have 3 problems now:
1. The output is shown when the process is finished - as it is a long process (maybe 20 minutes) it would be good to see what the child process is doing.
2. If this is not possible it would be good to show (maybe in console) that this process is working.
3. child process is only returning error streams, also when they are actually no error messages

October 21st, 2005, 01:47 AM
I have just another problem:

when I write:

mkdir "Folder name with blanks" - the folder with blanks is created

when I do the same with a java process:

Process mkdir = Runtime.getRuntime().exec("mkdir \"Folder name with blanks\"");

it creates following folders:


any ideas?

October 21st, 2005, 03:19 AM

Well I'm new to Java but can't you just do:

import java.io.File;

new File("Folder name with blanks").mkdirs();