[yole]

What exactly do you mean by "copyright and licensing"? JetBrains products do not violate any copyright or licenses from Oracle, and even if they change the license of future versions of Java, current versions are available for us to use. And Oracle has been investing into two different IDEs, NetBeans and JDeveloper.

[ed_balls]

API is copyrightable (see Google vs Oracle) JetBrains plugins depend on this API, so Oracle can say they are in the violation and demand a fee.