Client suddenly freezes. Upper left hand corner says (Not Responding) next to displayed server version. Pressing T or any shortcut turns mouse into the waiting symbol. Pressing the close button brings up that Java is not responding and asks for confirmation of closure. Upon exiting, the launcher then reopens and displays the inconvenience of the crash.
Log for this crash is linked as at attachment. This isn't the only log to have this error for me that I've had.