SDE for IntelliJ IDEA is a full-featured UML modelling tool seamlessly integrated with IntelliJ IDEA. SDE supports full software development life-cycle - analysis, design, coding, testing and deployment. You can draw UML diagrams (class, use case, sequence, collaboration, state, activity, component, deployment) in IntelliJ IDEA...
+MS Visio integration
+Round-trip engineering
+Plug-in and template support
+Import Rational Rose
+more