If i use scm.writeBytes other threads always freeze

[makarna35]

If i use scm.writeBytes other threads always freeze

Example:

runProgressBar();
// WriteToPort
            Object[] openPort = openComPort(selectedComPort.getSelectedItem().toString());
            scm = (SerialComManager) openPort[0];
            handle = (long) openPort[1];
            try {
                // Write delayInbytes
                scm.writeBytes(handle, messagesData.getBytes(), speedSlider.getValue());
                //System.out.println("WRITE COMPLATE : ");
                //System.out.println("write : " + scm.writeString(handle, textSpeedSliderStringValue, 0));
                portRepeatingRead();
            } catch (Exception e) {
                e.printStackTrace();
            }

public void runProgressBar() {
    loadingBar.setVisible(true);
    loadingBar.setStringPainted(true);
    threadProgressBar = new Thread(new Runnable() {
        @Override
        public void run() {
            int i = 0; 
            try { 
            while (i <= 100) { 
                // fill the menu bar 
                loadingBar.setValue(i + 10); 
  
                // delay the thread 
                Thread.sleep(messagePercent1); 
                i += 1; 
            } 
        } 
        catch (Exception e) { 
        } 
        }
    });
    threadProgressBar.start();
}

//-------------------------------------------------------//
runProgressBar(); function start before scm. But always freeze. after finished write port loadingBar.setVisible(true); work. why?