IDEA not showing JavaDoc for decompiled Java class files

Question

I don't see the documentation in my Maven project for Java dependencies that are decompiled from .class files. It does work for external Maven dependencies.

I have activated the following settings.

Settings->Importing->Automatically Download->Sources & Documentation

And also, right click pom.xml and download documentation there.

How can I make IDEA fetch documentation for these core Java files?

Refer screenshots below to see examples of both scenarios.

Answer 1

You need to make sure the sources are attached to the JDK configuration. It should work out of the box, but it could be that your JDK installation is incomplete and is missing the sources.

src.zip must be present in the Sourcepath of the JDK configuration:

Try reinstalling JDK from the official download page and configure it again in IntelliJ IDEA.