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.
If you want to stay within Eclipse: use free ObjectAid - discovers parents, nestings, associations.
If you want the tool, which in addition discovers and show children, usages, dependencies, annotations - then use free Class Visualizer.
I generally use Doxygen to create documentation because it has built-in support to generate inheritance diagrams. There is an Eclipse plug-in for Doxygen called eclox. It is not longer maintained since December 1st.
Doxygen is based on Graphviz. You could directly use LightUML, which is based on Graphviz to create UML diagrams in Eclipse.
Annotate your classes with Ecore's annotations, then you can import an Ecore file from them. You can initialize an Ecore diagram from them, or export it to UML, and initialize a class diagram from it.
来源：https://stackoverflow.com/questions/2272591/is-there-a-free-eclipse-plugin-that-creates-a-uml-diagram-out-of-java-classes