IBM WebSphere UML plugin: UML diagrams, use case modeling, textual analysis.
Editor: SDE for WebSphere is a UML CASE tool/plug-in tightly integrated with WebSphere. This UML modeling software supports full software lifecycle - analysis, design, implementation, testing,sphere walkthrough
and deployment. This UML CASE tool helps you build quality applications FASTER, better and cheaper. You can draw all types of UML Diagrams in WebSphere, reverse engineer Java code to class diagrams, generate Java code and generate documentation.

SDE-WS Features:
+Support UML version 2.1
+Business Workflow diagram
+ (New Feature)
+Handi-Selection (New Feature)
+Command-line operations (New Feature)
+User Interface Designer (Enhanced)
+Data flow diagram
+Use Case Details Editor - An all-in-one environment for specifying a general model specification and use case descriptions
+EJB Diagram - Visualize EJB systems
+EJB Code Generation
+ORM support - generate Java objects from database
+Database generation - ERD to database tables
+Database reverse - existing DBMS to ERD
+Reverse engineering - code to model, code to diagram
+Reverse engineering Java, C++, XML Schema, XML, .NET exe/dll, CORBA IDL, XML Schema and Python (Enhanced)
+Code Generation - model to code, diagram to code
+Java Round-trip engineering
+Automatic synchronization Between source code and diagrams
+Automatic diagram layout
+Modeling collaboratively with VP Teamwork Server, CVS and Subversion (Enhanced)
+Shape editor
+Import Rational Rose project, XMI/export XMI, Telelogic Rhapsody Project (New Feature)
+Support Stored Procedure and Database Trigger (New Feature)
+Export diagrams to JPG, PNG, SVG, EMF, PDF
+PDF/HTML/MS Word Report generator
+Multilingual support
+More...

Other UML Modeling Tools / UML Plugins:
Java Platform (Windows/Linux/Mac OS X):
+SDE for Eclipse
+SDE for Oracle JDeveloper
+SDE for Borland JBuilder
+SDE for IntelliJ IDEA
+SDE for NetBeans
+SDE for Sun ONE
+SDE for WebLogic Workshop

Windows Platform:
+SDE for Microsoft Visual Studio
you can free download SDE for IBM WebSphere (PE) for Windows 4.2 now.