How to use java program to run command prompt commands?

Question

this is my first time posting here, so I'm not really sure what to say/ask. Anyways, I am trying to make a simple java program that runs command prompt commands from the java program, mainly used for ping flood (ping flooding myself).

Here is my current code

public class Core extends JFrame {

JTextField ipTextField;

int packets = 0;

boolean running = false;

public Core() {
    super("Fatique");

    Container container = getContentPane();
    JButton bAttack = new JButton("Start Attack");
    JButton bStop = new JButton("Stop Attack");
    JPanel jPanel = new JPanel();

    container.setLayout(new FlowLayout());
    ipTextField = new JTextField("IP Address", 30);
    container.add(ipTextField);

    bAttack.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
            String input = ipTextField.getText();
            String[] value = input.split(":");

            int amountOfPackets = Integer.parseInt(value[1]);

            exec("cmd /c" + input + " -t -n " + amountOfPackets);
            running = true;
        }
    });

    bStop.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
            stop();
        }
    });

    if(!running) {
        jPanel.add(bAttack);
    } else {
        jPanel.add(bStop);
    }

    add(jPanel);
}  

public void exec(String cmd) {
    try {
        Process p = Runtime.getRuntime().exec(cmd);
        System.out.println(getOutput(p) + " - " + getPacketsSent());
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public String getOutput(Process p) {
    String output = null;

    try {
        BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
        String line = null;
        while ((line = in.readLine()) != null) {
            output = line;
            packets++;
        }

        return output;
    } catch (IOException e) {
        System.err.println(e.getStackTrace());
    }

    return null;
}

public int getPacketsSent() {
    return packets;
}

public void stop() {
    exec("cmd /c break");
    running = false;
}

public static void main(String[] args) {  
    Core c = new Core();
    c.setSize(500, 300);
    c.setVisible(true);
    c.setResizable(false);
    c.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    c.setLocationRelativeTo(null);
}

I'm quite new at java, so that might not do what I want it to do. What I want it to do is I enter an ip address in the textfield, and split it with ":", and after that the amount of packets, for instance

127.0.0.1:100

Though now when I try to use that ip and packet amount, it returns "null - 0" (from exec method), and I'm not even sure if it did anything related to ping.

What I am trying to accomplish is as I already said, ping flood myself, and then output whatever I get as response, though I have no idea if this code does anything even related to that, I mostly use logic when coding java.

 public String getOutput(Process p) {
    String output = null;

    try {
        BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
        String line = null;
        while ((line = in.readLine()) != null) {
            output = line;
            packets++;
        }

        return output;
    } catch (IOException e) {
        System.err.println(e.getStackTrace());
    }

    return null;
}

Could someone explain me why my code code is not working how I want it to work? Please don't judge, as I already said, I'm quite new to java programming.

EDIT: Here is a quick "informative" explanation of what I am trying to accomplish.

1. I type in an ip address and how many packets I want to send. In this explanation, I am using localhost ip, and 5 packets.

2. I start the attack. At this part, I want the program to run cmd prompt command

   ping 127.0.0.1 -t -n 5

   127.0.0.1 being the ip that I put in the textfield in my program, and 5 is the amount of packets I put in the textfield.

3. I started the attack, so this is what should happen in the command prompt:

   The language is Finnish, but still the same thing.

   This is the basic explanation of what I am trying to accomplish, hopefully someone understood and can help/tell why my code is not working, or is working but not printing the proper lines in eclipse console.

Answer 1

Try something like this:

try {
       Runtime rt = Runtime.getRuntime();
       Process p = rt.exec("ping 192.168.16.67");
       InputStream in = p.getInputStream();
       OutputStream out = p.getOutputStream ();
       InputStream err = p.getErrorStream();
       p.destroy();
} catch(Exception exc) {}

Then, you'll have to read the out variable to parse the ping command output continuously.