How should one distribute the Javadoc for a Library?

I am writing a custom library. It's build into a .jar archive. I am fully able to generate the javadoc, but I don't know how I should distribute it?

1. Put it in the same .jar with the library
2. Put it in a different .jar
3. Some other way?

And how to include the javadoc in another project that uses my lib?

1. If I had put it in the same .jar, should I have written something in the manifest?
2. If it's in a separate .jar, is including it in the project enough?

I am using NetBeans 9.1.