Interact with openconnect in java processbuilder

I am attempting to establish a VPN connection using a ProcessBuilder in Java. However, the process seems to block, and entering my password has no effect.

I am unable to include my username and password directly in the command line because they can change over time, and for security reasons, I am sometimes prompted for a second password.

Any help is welcome

Minimalist sample :

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

    public class VPNConnectionHandler {
    
        public static void main(String[] args) {
            String[] command = {"sudo", "openconnect", "--background", "--protocol=nc", "--user=user", "serveradress"};
    
            try {
                ProcessBuilder processBuilder = new ProcessBuilder(command);
                Process process = processBuilder.start();
    
                BufferedReader stdInput = new BufferedReader(new InputStreamReader(process.getInputStream()));
                BufferedReader stdError = new BufferedReader(new InputStreamReader(process.getErrorStream()));
                OutputStreamWriter stdOutput = new OutputStreamWriter(process.getOutputStream());
    
                String line;
                boolean passwordPrompted = false;
    
                while ((line = stdInput.readLine()) != null || (line = stdError.readLine()) != null) {
                    if (line != null) {
                        System.out.println(line);
                        if (line.toLowerCase().contains("password:")) {
                            System.out.println("password asked");
                            if (!passwordPrompted) {
                                System.out.print("password ");
                                BufferedReader consoleReader = new BufferedReader(new InputStreamReader(System.in));
                                String password = consoleReader.readLine();
    
                                
                                stdOutput.write(password + "\n");
                                stdOutput.flush();
                                passwordPrompted = true;
                            }
                        }
                    }
                    if (line == null) {
                        break;
                    }
                }
                int exitCode = process.waitFor();
                System.out.println("Process exited with code " + exitCode);
    
            } catch (IOException | InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

Using G00se idea, my concern is I don't know how to redirect the output so I can read it in Java and input via the code :

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;

    public class VPNConnectionManager {
    
        public static void main(String[] args) {
            String[] command = {"sudo", "openconnect", "--background", "--protocol=nc", "--user=user", "server"};
    
            try {
                ProcessBuilder processBuilder = new ProcessBuilder(command).inheritIO();    
                Process process = processBuilder.start();
        
                //password request
                //scanner or what ever to I can fill in the password


                int exitCode = process.waitFor();
                System.out.println("Process exited with code " + exitCode);
    
    
            } catch (IOException | InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

Maybe this can help me, but no idea how to make it work here :

https://github.com/agavrilov76/ExpectIt