Actually, the best example of that is already mentioned in the article:
"With Enonic XP, the combination of Java and JavaScript is used to speed up the development process and allow frontend developers to implement backend services. I saw that this was a very popular approach to develop software more effectively, and wanted everyone to be able to use the technology for free and in existing investments. PurpleJS was born."
PurpleJS is the core of Enonic XP, made available separately as an open source project (well, both are open source).