There is perhaps no area of programming tools where competition is as intense
as in the Java IDE market. Even though there are only four primary players –
Eclipse, NetBeans, IntelliJ IDEA, and Oracle JDeveloper (Rational and
CodeGear JBuilder build on Eclipse) -- all vendors except Oracle watch their
competitors intently and rush to add new differentiating features. (Oracle's
product is primarily aimed at internal use and at buyers of the company's
Fusion Middleware stack.) The competition is most intense between Eclipse,
NetBeans, and IntelliJ IDEA, likely because those products have the most
active communities of users and those users tend to be personally attached to their
preferred environment. Of the three, only Eclipse and NetBeans are free and open
source.