Can't see JavaDocs in JDK in Intellij IDEA?

Question

Java

JavaDocs comments are not visible in the source codes of standard classes, and what is strange IDEA writes above each class

Decompiled .class file, bytecode version: 52.0 (Java 8)

.

Using:
IntelliJ IDEA 2018.2.3 EAP (Ultimate Edition)
Build #IU-182.4323.6, built on August 22, 2018

And Ubuntu 18.04 system

Answer 1

Installing Oracle JDK instead of Openjdk helped me, it comes with Ubuntu by default. There were simply no comments in Openjdk