Come on, that’s a cheap reason (for Java, for open source db I would also go with postgre but for different reasons). Java is one of the very few languages with a full specification (not “whatever our compiler does, that’s the spec”), it has plenty of fully independent full implementations that even pass one of the most detailed test suites for complete spec-compliance, and the platform is so so much ingrained in the biggest corporations that any one of the following companies could easily, single-handedly finance the future of Java if anything were to happen: Apple, Google, Microsoft, Amazon, Alibaba.

And for all the bad things one can without doubt throw at Oracle, they are surprisingly good at shepherding the language and platform. It has been growing in a very good direction with fast update cycle, it has state-of-the art research and development going on, and with Loom on the near horizon and Valhalla on the slightly further horizon I would say Java has one of the brightest futures ahead. Like, Valhalla would bring automagically a huge performance improvement for free, and Java is very competitive in performance as is.