This seemed to me like the easiest thing to find, a simple way to display my classes as UML in eclipse
But except this: http://java2uml.gforge.enseeiht.fr/ and this http://sourceforge.jp/projects/amateras/releases/ I haven't found any new, maintained and "good" implementation (with all due respect to the above two)
Anything else I've missed?
Did you consider
Creating UML 2 diagrams with Eclipse UML2 Tools - Tutorial ?
I had older references for such tools, but the new ones are build upon UML2 project (described in the tutorial). MDT-UML2Tools is in the making, Omondo is there, but not free.
Papyrus UML, for instance, is based on UML2 Tool.
There is a tool in the Marketplace that can do the above (UML Class, Package and Interaction). It's called ModelGoon. Last tried in July 2018.
The full list is available at Eclipse marketplace.