I work for several very large telcos and I have been, so far, able to avoid both .NET and Java. Last time I wrote C# code was because Microsoft (then a client) demanded we run our application on a Windows server. I wrote a proxy that sat in front of the application (which ran on a Linux machine).
Our consulting company does mostly Fortune 500 and DAX 30 customers.
After 5 years of almost only Java projects, most of the new contracts are coming from .NET land.
Better explained?