UML Plugin for Eclipse: UML diagrams, Rational Rose, XMI import/export.
EditByBSEditor: SDE for Eclipse is a UML CASE tool/plug-in tightly integrated with Eclipse. This UML CASE tool supports full software lifecycle - analysis, design, implementation, testing and deployment. This UML tool helps you build quality applications FASTER, better and cheaper. You can draw all types of UML Diagrams in Eclipse, reverse engineer Java code to class diagrams, generate Java code and generate documentation.

SDE Features:
+the latest UML support (use case diagram, sequence diagram, collaboration diagram, class diagram, statechart/state diagram, activity diagram, component diagram, deployment diagram, object diagram, package diagram)
+Use case modeling (use case description, scheduling...)
+Textual analysis for identifying candidate classes, actors, use cases, flow of events...
+Business Workflow diagram
+CRC Card diagram
+Reverse engineering - code to model, code to diagram (Java to UML models, Java to UML diagram)
+Instant Reverse for Java, C++, Dot NET exe/dll, XML, XML Schema, CORBA IDL
+Code Generation - generate code, model to code, diagram to code (UML to code, UML model to Java)
+Incremental round-trip engineering
+Automatic synchronization Between source code and diagrams
+Automatic diagram layout - rearrange classes and connectors in UML diagrams in different styles
+Import Rational Rose
+Import/export XMI
+Export diagrams to JPG, PNG, SVG
+Microsoft Visio Integration - draw UML diagrams with MS Visio shapes
+Report generator for generating UML documentation to HTML or PDF
+Plug-in and template
+Version control
+Multilingual support
+More...

Other UML Modeling Tools / UML Plug-ins:
Java Platform (Linux/Windows/Mac OS X):
+SDE for Eclipse
+SDE for Oracle JDeveloper
+SDE for IBM WebSphere (WSAD)
+SDE for Borland JBuilder
+SDE for IntelliJ IDEA
+SDE for NetBeans
+SDE for Sun ONE
Windows Platform:
+SDE for Microsoft Visual Studio .NET
+More SDE... you can free download SDE for Eclipse (CE) for Linux 5.2 now.