jmap dump not working

no exception is thrown but I still cant find the dump.bin file in my desktop folder, is my path wrong?

 public static void dumpHeap()
        {
            System.out.println("dumping data");

            String name = ManagementFactory.getRuntimeMXBean().getName();
            System.out.println("name :" + name);
            String pid = name.substring(0, name.indexOf("@"));
            System.out.println("pid :" + pid);

            String[] cmd = { "jmap", "-dump:file=/Users/MyName/Desktop/dump.bin", pid };
            Process p;
            try {
                p = Runtime.getRuntime().exec(cmd);
            } catch (IOException e) {
                e.printStackTrace();
            }

I had to force it using -F

public static void dumpHeap()

    {
        System.out.println("dumping data");

        String name = ManagementFactory.getRuntimeMXBean().getName();
        System.out.println("name :" + name);
        String pid = name.substring(0, name.indexOf("@"));
        System.out.println("pid :" + pid);

        String[] cmd = { "jmap", "-dump:file=/Users/MyName/Desktop/dump.bin", "-F", pid };
        Process p;
        try {
            p = Runtime.getRuntime().exec(cmd);
        } catch (IOException e) {
            e.printStackTrace();
        }