Java application won't start openvpn configuration file via exec function

I am trying to write a small Java application that starts an openvpn configuration file. Therefore I first changed the sudoers file on my mac to:

sudoers

USERNAME ALL=(ALL:ALL) NOPASSWD: /usr/local/Cellar/openvpn/2.4.6/sbin/openvpn


I got the USERNAME via the command whoami. This part is working fine, because when I now type

USERNAME

whoami

sudo openvpn /directory/of/openvpn/file.ovpn


into the terminal on my mac. I don't have to insert any password and the openvpn configuration file starts running. After that I now want to use my Java application to do the same job. Therefore I have the following setup:

public class Connector

public static String executeCommand(String... command)
StringBuffer output = new StringBuffer();
Process p;
try
p = Runtime.getRuntime().exec(command);
System.out.println(p.waitFor());
InputStreamReader in = new InputStreamReader(p.getInputStream());
BufferedReader reader = new BufferedReader(in);
String line = "";
while ((line = reader.readLine()) != null)
output.append(line + "n");

p.destroy();
reader.close();
catch (Exception e)
e.printStackTrace();

return output.toString();



public static void main(String args)
String command = new String[3];
command[0] = "/bin/sh";
command[1] = "-c";
command[2] = "/usr/bin/sudo -S /usr/local/Cellar/openvpn/2.4.6/sbin/openvpn /directory/of/openvpn/file.ovpn";

String result = Connector.executeCommand(command);
System.out.println(result);




For command[2] I also tried without the flag -S as well as providing the password via echo password | sudo command. For command[0] I also used /bin/bash instead of /bin/sh. But everything leads to the same result. The application runs infinitely. No output within the console. And the openvpn configuration file was not opened, because when I now type

command[2]

echo password | sudo command

command[0]

/bin/bash

/bin/sh

killall openvpn


into the terminal on my mac I get the information that there is no open connection.

No matching processes belonging to you were found


If I don't use the sudo command

command[2] = "/usr/local/Cellar/openvpn/2.4.6/sbin/openvpn /directory/of/openvpn/file.ovpn";


I get an output that says that I have not the permissions to run the configuration file. This is the same output that I get when I type the command above into the terminal on my mac manually.

Opening utun (connect(AF_SYS_CONTROL)): Operation not permitted (errno=1)


UPDATE

I changed the function executeCommand to

executeCommand

public static String executeCommand(String... command)
try
Runtime rt = Runtime.getRuntime();
Process proc = rt.exec(command);
InputStream stderr = proc.getErrorStream();
InputStreamReader isr = new InputStreamReader(stderr);
BufferedReader br = new BufferedReader(isr);
String line = null;
System.out.println("<ERROR>");
while ( (line = br.readLine()) != null)
System.out.println(line);
System.out.println("</ERROR>");
int exitVal = proc.waitFor();
System.out.println("Process exitValue: " + exitVal);
catch (Exception e)
e.printStackTrace();




Now I get an error message in my console that says

<ERROR>
ifconfig: ioctl (SIOCDIFADDR): Can't assign requested address
route: writing to routing socket: File exists


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