On Jan 13, 2010, at 11:00 AM, Sittampalam, Ganesh wrote:

Type classes allow you to dispatch based on return type, and on the instantiations of generic parameters. Neither of these things is reasonably possible with interfaces.

There is recent work that generalises the capabilities of interfaces in Java:

http://www.informatik.uni-freiburg.de/~wehr/publications/WehrLammelThiemann2007.html

http://www.informatik.uni-freiburg.de/~wehr/publications/WehrThiemann2009.html

http://www.informatik.uni-freiburg.de/~wehr/publications/Wehr2009.html

Seeing type-class features in Java disguise highlights the differences between the two concepts that you mention.

Sebastian

Underestimating the novelty of the future is a time-honored tradition.

(D.G.)