The Best active IDEs for developing Java application
 

Eclipse:
A dedicated Java IDE, Eclipse get listed as one of the big three of Java IDEs. (free)
Eclipse also supports application development in several programming languages via plugins. e.g C, C++, Clojure, Groovy, Haskell, PHP, Ruby, etc.

IntelliJ IDEA:
It is avaliable in 2 different editions, an Apache 2 Licensed community edition(free), and a proprietary commercial edition.

Netbeans:
It is the official IDE for Java 8.