What is the official site with descriptions of functions and classes for Java?

Question

Java

Each site has its own manual.
From JAVA where to get material on functions and so on in Russian is mandatory

Answer 1

https://docs.oracle.com/en/java/

Answer 2

There is no documentation for the Java API in Russian. At least up to date.

Answer 3

well, about all the classes from the source:
https://docs.oracle.com/javase/8/docs/api/index.html
and what is this?

required in Russian