Yeah, lots of corporate backend code is Java, and Java is a great choice for backend/server code. I've never seen Oracle anywhere, though, not in banks and not in governments. I've mostly seen Postgres and MSSQL and some MongoDB.
When something has been there for 20+ years switching costs are big.
Regulatory thing for us, some workloads need production support for the data tier for various boring legal and compliance reasons, so our choices are kida limited to oracle and, these days, mongo, who have made massive inroads to enterprise in the last couple years.
Personally, I prefer Mongo.