Socket write in GUI Client

Question

I have a GUI Swing client that is communicating with a Server with Sockets.
Currently, when a message needs to be sent ( Socket.write ), I am just passing the message to my thread-safe sendMessage() method.
I have an application currently calling this from the Event Thread without issue, but I have heard that this could create a possible dead-lock, but I haven't been able to pinpoint the reasoning behind this.
What pitfalls occur if this method, which writes to the Socket's OutputStream directly, is called from the GUI Event Thread?
Thanks in Advance.

Answer 1

Thank you all for the input.
I think what I will do is dispatch a new Thread to do the sendMessage if it is invoked from within the GUI Event Thread.
Which would be better? Create a new anonymous thread or use SwingUtilities.invokeLater ?
1)
     void actionPerformed( ActionEvent e )
             new Thread( new Runnable() { void run() { sendMessage(data); } } ).start();
     }2)
     void actionPerformed( ActionEvent e )
             SwingUtilities.invokeLater( new Runnable() { void run() { sendMessage(data); } } );
     }