Abstract classes and interfaces in Java serve fundamentally different purposes. Learn the differences between these Java language elements and how to use them in your programs.

For JavaOne 2010 , Mark Reinhold will be presenting "JDK 7 and Java SE 7" (S314556) at 10 am on Monday, September 20, at Hilton San Francisco in the Grand Ballroom AB.

Interested in Java functional programming? The first place you need to start, especially if you use the Streams API, is with this Java Function interface example.