These days if you are doing serious work, you simply use Java. Especially if you want something running for years. Java is really the only option you have.
A decade back I interviewed at a major telecommunications firm. Python was the new fashion then, they were trying to rewrite a fairly big Java code base to Python. Anyway I didn't get the job. My friend did. After a few years of this they realised, Python was not a serious alternative for an application of that nature. And abandoned it midway.
I know several other banks that have had a similar arc. Python is an amazing glue language and perfect for lots of automation and adhoc glue work. Its just not meant to be a serious alternative for long term, stable applications which are typically written in Java/C++.
Other languages like golang have come up in the past. While they are really good for smaller applications. They are just not there for something serious. 'Simplicity' has different meanings in different contexts. Either way, I think both Python and Java are here to stay and will be used for tasks where they are good at.
But we are now past the 'Python for everything' days.