David Flanagan discusses his favorite API features in J2SE 5.0. He says that these are not necessarily the feaures that are most important or most useful, but the features that he thinks are the coolest or most elegant.

The features are:

• Callable and Future Interfaces
• Varargs
• Autoboxing
• Abilities
• Hexadecimal Floating Point Literals

Reference:
>> Five Favorite Features from 5.0
>> DavidFlanagan.com

Related:
>>
What’s new in J2SE 5.0?
>> Books by David Flanagan