At last found a solution that works for me. It may be useful for others in this Stack Overflow Q&A titled: Sudo In Java Process.
The solution involves a fair amount of Java so I'm only going to reference the answer in the original link mentioned above. Here's an example using the code from that answer.
public static void main(String[] args) throws IOException, InterruptedException {
String password = LinuxCommand.getPasswdForRoot();
System.out.println("stdout of 'id':");
Process p = LinuxCommand.runFromRoot("id",password);
System.out.print(streamToString(p.getInputStream()));
System.out.println("stdout of 'fdisk -l':");
p = LinuxCommand.runFromRoot("fdisk -l",password);
System.out.print(streamToString(p.getInputStream()));
}
The actual implementation of api used above:
import java.awt.BorderLayout;
import java.io.IOException;
import java.io.InputStream;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
public class LinuxCommand {
static InputStream is;
static byte[] buff = new byte[8192];
static int n;
public static String getPasswdForRoot() throws IOException {
Process p = Runtime.getRuntime().exec(new String[]{"sh","-c","sudo -S id"});
is = p.getErrorStream();
n = is.read(buff, 0, 8192);
String text = new String(buff,0,n);
if(text.contains("root"))return null; //not set password
JPanel panel = new JPanel(new BorderLayout());
JLabel lab = new JLabel(text);
panel.add(lab,BorderLayout.NORTH);
JPasswordField password = new JPasswordField();
panel.add(password,BorderLayout.SOUTH);
JOptionPane.showMessageDialog(null, panel);
byte[] passwd = (new String(password.getPassword())+"\r\n").getBytes();
p.getOutputStream().write(passwd);
p.getOutputStream().flush();
n = is.read(buff, 0, 8192);
if(n==-1) return new String(password.getPassword());
text = new String(buff,0,n);
while(true) {
lab.setText(text);
JOptionPane.showMessageDialog(null, panel);
p = Runtime.getRuntime().exec(new String[]{"sh","-c","sudo -S id"});
is = p.getErrorStream();
n = is.read(buff, 0, 8192);
passwd = (new String(password.getPassword())+"\n").getBytes();
p.getOutputStream().write(passwd);
p.getOutputStream().flush();
n = is.read(buff, 0, 8192);
if(n==-1) return new String(password.getPassword());
text = new String(buff,0,n);
}
}
public static Process runFromRoot(String command, String password) throws IOException {
byte[] passwd = (password+"\n").getBytes(); //for OutputStream better is byte[]
Process p = Runtime.getRuntime().exec(new String[]{"sh","-c","sudo -S "+command});
p.getOutputStream().write(passwd);
p.getOutputStream().flush();
return p;
}
}
Along with the output when that code is executed:
stdout of 'id':
uid=0(root) gid=0(root) grupy=0(root)
stdout of 'fdisk -l':
Disk /dev/sda: 640.1 GB, 640135028736 bytes
głowic: 255, sektorów/ścieżkę: 63, cylindrów: 77825, w sumie sektorów: 1250263728
Jednostka = sektorów, czyli 1 * 512 = 512 bajtów
Rozmiar sektora (logiczny/fizyczny) w bajtach: 512 / 4096
Rozmiar we/wy (minimalny/optymalny) w bajtach: 4096 / 4096
Identyfikator dysku: 0xc56b9eef
Urządzenie Rozruch Początek Koniec Bloków ID System
/dev/sda1 2048 37064703 18531328 27 Hidden NTFS WinRE
/dev/sda2 * 37064704 37269503 102400 7 HPFS/NTFS/exFAT
/dev/sda3 37269504 456711884 209721190+ 7 HPFS/NTFS/exFAT
/dev/sda4 456711946 1250258624 396773339+ f W95 Rozsz. (LBA)
Partycja 4 nie zaczyna się na granicy bloku fizycznego.
/dev/sda5 456711948 810350729 176819391 7 HPFS/NTFS/exFAT
Partycja 5 nie zaczyna się na granicy bloku fizycznego.
/dev/sda6 810350793 862802954 26226081 7 HPFS/NTFS/exFAT
Partycja 6 nie zaczyna się na granicy bloku fizycznego.
/dev/sda7 862803018 1020078408 78637695+ 83 Linux
Partycja 7 nie zaczyna się na granicy bloku fizycznego.
/dev/sda8 1020079368 1229791814 104856223+ 7 HPFS/NTFS/exFAT
/dev/sda9 1229791878 1250258624 10233373+ 7 HPFS/NTFS/exFAT
Partycja 9 nie zaczyna się na granicy bloku fizycznego.
expect
script to input your password.