Eclipse how to link a jar containing javadocs/source with its binary?

Question

I would like to have the javadoc comments contained in a jar file show in eclipse when I hover over a class.

For example, after downloading JODA-2.0, three jars are

Answer 1

Right-click on the jar (the one with the class files), choose "Properties", the "Javadoc location", and choose the jar file with the javadoc. Do similarly for the source jar, using "Java source attachment".