Update JLabel from another thread

Dear guys, I'm having swing related problem. I cannot share the code since it's against the company policy, so I will try my best to explain the problem.

In short, I have created a class that extends JWindow that contains a JLabel. This JLabel's text is updated randomly through a timer object, that instantiates a TimerTask every 50 ms using the scheduleAtFixedRate method. The values in the JLabel are retrieved by calling a method in a separate thread (let's call it transmission thread) that handles transmitting data to a certain device. The problem is that the JWindow appears on the screen with no content whatsoever till the transmission to the de开发者_运维技巧vice is over, then I'd be getting the last result of the transmission thread. What would the problem be?

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Instead of java.util.Timer, javax.swing.Timer may be more convenient, as seen in this example.

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The problem is that you access swing components in other threads than the Event Dispatch Thread (EDT). This is forbidden.

The javadoc of every swing componenthas a link to this page : http://download.oracle.com/javase/6/docs/api/javax/swing/package-summary.html#threading, where the threading policy is explained in details.