Among the core languages - C++ > Java > Go > Python. Also possible to have a lot of impact with JS (client) > Java/Kotlin (Android) > ObjC/Swift (iOS).
Most good devs - and basically all devs who make it to L5+ (Senior SWE) - will end up working in multiple languages, though. There are a bunch of proprietary ones as well, some of which are open-source (like Protobufs and Bazel) and a few I'm not at liberty to discuss. L6+ your soft skills (communication, EQ, management, prioritization) become more important than your technical skills.
I’m curious about the split between where C++ is often found and where Java is used.
Is it more like less latency critical (or compute cost) services are in Java, and things like Search core are C++? Are there legacy reasons for one over the other?
If you were going to spend time gaining experience in Java or C++, with a long term plan of working on something really interesting and high impact there, which would it be?
Most good devs - and basically all devs who make it to L5+ (Senior SWE) - will end up working in multiple languages, though. There are a bunch of proprietary ones as well, some of which are open-source (like Protobufs and Bazel) and a few I'm not at liberty to discuss. L6+ your soft skills (communication, EQ, management, prioritization) become more important than your technical skills.