Vaadin7 two problems. Camera,refresh.

Hi i am newbie in Vaadin, and i try to create project using pi4j. I have two problems, please help me to resove it.
In my Raspberry i have camera streaming video on adress localhost:8081, how can i put this stream to my vaadin webpage?
I use Rs232 like this:

// create an instance of the serial communications class
final Serial serial = SerialFactory.createInstance();
// create and register the serial data listener
serial.addListener(new SerialDataListener()
public void dataReceived(SerialDataEvent event) {
// print out the data received to the console
layout.addComponent(new Label(event.getData()));
and RS send message to console, but on Vaadin page only shown it if i click some button. I don’t know how to show this data every time when meesage came to my app.

Please help.