I guess you already know that you get the JavaDoc for a class or member when hovering the mouse cursor over the name, and can increase the size of the popup via F2. I also assume you know about the JavaDoc view.
Given that, I'd advice to try the JDocs plugin:
http://www.jdocs.com/plugins/eclipse/index.html
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
