Java is absolutely massive for a huge variety of applications, most of them servers and daemons. The most common user-facing Java implementations are probably Android and Minecraft, but behind the scenes it powers everything from blogs to logistics to networking equipment to SIM cards.

Oracle's own OpenJDK is free but they will only let consumers download Java 8 for free, that's why companies like Jetbrains ship JDKs with their products.

Google is in the middle of moving ChromeOS to Android, they're not replacing Android with Fuchsia any time soon.