The eco-system largely defines the programming language to use. There are some ways to escape that and people try to do that all the time with huge costs, but o

The eco-system largely defines the programming language to use. There are some ways to escape that and people try to do that all the time with huge costs, but on the JVM the majority of software is written in Java, on .net it is written in C# and on iOS it is Objective-c / Swift.