Try replacing

String[] command = {"/teste/teste_back/script.sh, "+argument1+", "+argument+""};

with

String[] command = {"/teste/teste_back/script.sh", argument1, argument};

Refer ProcessBuilder for more information.

ProcessBuilder(String... command)

Constructs a process builder with the specified operating system program and arguments.

"(actually it's "ls" but it should work exactly the same way)"

No, it is not. Because the 'ls' process returns immediately after its call. Your omixplayer at the other hand is interactive and will accept commands at runtime.

What you have to do:

• create a class which implements Runnable and let this class read from the prs.getInputStream(). You will need this because the .read() will block and wait for new data to read.

• get the OutputStream of the Process object (prs.getOutputStream()). Everything you write to the OutputStream will be read from your omixplayer. Don't forget to flush the OutputStream and every command needs an "\n" at the end to be executed.

Like that:

public class TestMain {
    public static void main(String a[]) throws InterruptedException {

        List<String> commands = new ArrayList<String>();
        commands.add("telnet");
        commands.add("www.google.com");
        commands.add("80");
        ProcessBuilder pb = new ProcessBuilder(commands);
        pb.redirectErrorStream(true);
        try {

            Process prs = pb.start();
            Thread inThread = new Thread(new In(prs.getInputStream()));
            inThread.start();
            Thread.sleep(2000);
            OutputStream writeTo = prs.getOutputStream();
            writeTo.write("oops\n".getBytes());
            writeTo.flush();
            writeTo.close();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

class In implements Runnable {
    private InputStream is;

    public In(InputStream is) {
        this.is = is;
    }

    @Override
    public void run() {
        byte[] b = new byte[1024];
        int size = 0;
        try {
            while ((size = is.read(b)) != -1) {
                System.err.println(new String(b));
            }
            is.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
}

P.S.: Keep in mind this example is quick an dirty.

The cd command you execute with the first ProcessBuilder affects only that child process, it does not change the working directory of the main executing program. When you run the second ProcessBuilder, it will have the working directory as the main program, completely unaffected by the cd executed by the previous ProcessBuilder.

To execute a program from a different directory, use the directory(...) method of ProcessBuilder:

String command[] = {"javac", JAVA_FILE_LOCATION};
ProcessBuilder processBuilder = new ProcessBuilder(command).directory(new File("path/to/dir"));
Process process0 = processBuilder.start();

Btw, the path "/Users/Desktop/piano.java" looks very strange. The path to a user's desktop on a Mac is usually /Users/username/Desktop, so the path in your code implies that your username is "Desktop", which is very unusual.

And, to make it easier to work with the program, I suggest to put the base directory path (/Users/username/Desktop) in a variable, rather then hardcoding it at multiple places. That way it will be easier to make changes, no need to edit at multiple places.