The default implementation of the Document interface (AbstractDocument) supports asynchronous mutations. If this feature is used (i.e. mutations are made from a thread other than the Swing event thread), the listeners will be notified via the mutating thread. This means that if asynchronous updates are made, the implementation of this interface must be threadsafe!

The DocumentEvent notification is based upon the JavaBeans event model. There is no guarantee about the order of delivery to listeners, and all listeners must be notified prior to making further mutations to the Document. This means implementations of the DocumentListener may not mutate the source of the event (i.e. the associated Document).