Java – what is the difference between callbacks and listeners

java

In blackberry we can override keyChar() method and capture the keypress event or we can register onKeyPressListener. i know, onKeyListener is observer pattern.

In android also there is a KeyEvent.callback and onKeyListener

Both are events why we no need to register for keyChar event.
what is the difference between both pattern?

Best Answer

There can be many listeners for some type of event, but only one callback.