The Java market isn't booming, it's a resource hog on any system I've used it. I need 16 gibibytes of RAM in my laptop just to run Android Studio and Visual Studio Code at the same time, among everything else I have open. The only market I see Java developers wanted right now is Android and that isn't even pure Java anymore, it requires special knowledge of their proprietary views and intents.
.NET, as much as I hate it, is much more popular right now and pays a lot better in my experience. I just refuse to work with anything Microsoft because I don't want my blood pressure to increase.