Now the million dollar Question - Why on this Planet do we want a callback? When we pass a parameter, method being invoked gets the information (ie parameter value etc). What is returned is a result primitive or Object which provides only meager flow of info. Callback mechanism however allows a two-way communication channel between caller and callee.
Visitor Pattern is a classic example to demonstrate how Callback technique should ideally be used
~ Pratibha Malhotra<br /> <br />Sun Certified Java Programmer<br />SCEA 1.4 (In Progress)<br />~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />"Many of life's failures are people who did not realize how close they were to success when they gave up!!"