There are a lot more Java libraries than Objective-C libraries. Especially at Google.
We write a lot of Java at Google, but I wouldn't call anyone a "Java programmer". We're just programmers. And like all programmers, if we can save time by writing a tool and letting the computer do some work, we will. Laziness, impatience, hubris, and all that.
My 5-engineer team at Google all write java day-to-day. But we've all needed to write python, especially scripts, and have it properly checked in and maintained. Not sure how you could get by most places in the company without being able to do that. Besides, skill in other languages is an asset; I've written C++ client library code to push for broader adoption of my project.
We write a lot of Java at Google, but I wouldn't call anyone a "Java programmer". We're just programmers. And like all programmers, if we can save time by writing a tool and letting the computer do some work, we will. Laziness, impatience, hubris, and all that.