This example program will execute the external commands and capture the output.

Java Code:
import java.io.*;

public class CommandExection {

public CommandExection(String commandline) {

try {
 	String line;
 	Process p = Runtime.getRuntime().exec(commandline);
 	BufferedReader input =
 	new BufferedReader
 	(new InputStreamReader(p.getInputStream()));

 	while ((line = input.readLine()) != null) {
 		System.out.println(line);
 	}

 	input.close();
} catch (Exception err) {
 	err.printStackTrace();
}
}

public static void main(String argv[]) {
 	new CommandExection("c:\\CompChamps.exe");
}