Is it possible to use other JVM languages such as Scala and Clojure for developing an IntelliJ IDEA plugin? Or do we have to use Java for this purpose? I could find no pointers on this on web, hence posting the question here.
Yes, it is entirely possible.
Any plugin essentially is a set of extensions for several extension points which IDEA API provides. These extensions are regular java classes implementing predefined interfaces, and these classes are referenced to in the manifest. Also, you can bundle any libraries along with the plugin. So, if your language of choice allows implementing interfaces and finding out resulting class names, then nothing prevents you writing plugins in it.
来源：https://stackoverflow.com/questions/15989395/intellij-idea-plugin-development-in-other-jvm-languages