Execute an external program and capture the output import java.io.*; public class CmdExec { public CmdExec(String cmdline) { try { String line; Process p = Runtime.getRuntime().exec(cmdline); // jdk1.0.2 DataInputStream input = new DataInputStream(p.getInputStream()); // jdk1.1.1 // BufferedReader commandResult = // new BufferedReader // (new InputStreamReader(p.getInputStream())); while ((line = input.readLine()) != null) { System.out.println(line); } input.close(); } catch (Exception err) { System.out.println("EXEC failed: " + err.toString()); err.printStackTrace(); } } public static void main(String argv[]) { /* ** javac CmdExec tree.com ** javac CmdExec "tree.com /a" */ new CmdExec(argv[0]); } } You can include a path for the program to be executed. On the Win plateform, you will have problem if the path contains spaces in it. To fix the problem, put the path in quotes. public class Test { public static void main(String[] args) throws Exception { Process p = Runtime.getRuntime().exec( ""c:/program files/windows/notepad.exe""); p.waitFor(); } }