In Qt GUIs it is very convenient use signals & slots - it decouple events passing. When I create some widget that throw signal, I don't have to know in advance who can get it, and later with connect I specify connections.
What is parallel in Java/Swing? Can you point to good resources on this issue?
If none of the existing EventListener implementations meet your requirements, you can create your own custom event. Every JComponent contains a field of type EventListenerList. You can use the approach outlined in the EventListenerList API to enable your custom JComponent subclass to fire your custom event.
Regarding the signal/slot mechanism, Swing has several ways to implement the observer pattern, outlined here.
This Event Listener tutorial goes through the basics of handling events with listeners.
Connecting your slot for a signal is analogous to adding your EventListener to an event-producing object.
来源：https://stackoverflow.com/questions/6202803/swing-replacement-for-qt-signal-slots