Java wasn't the hyped enterprise OOP language in 1996 that it became in the 2000s. Back then, it was a little-used experimental language, initially for mobile apps (remember Oak?) but gaining some traction in applets. Sorta like C++, but they'd removed all the tricky bits. I remember picking it up in 1997 and thinking how elegant it seemed compared to C++.

It was basically like Go is now.

As for what it's written in now: mostly C++ but some Java in the webserver and auxiliary services. Other Google products are mostly Java. Most internal tools were Python but a bunch have been recently rewritten in Java. Go is catching on with some early-adopter teams.

C++