UML CASE tool - UML diagrams, use case modeling, reverse engineering and more...
Visual Paradigm for UML is a professional UML tool that supports complete software lifecycle - object-oriented analysis, object-oriented design, construction, testing and deployment. The UML modeling software helps you build quality applications FASTER, better and at lower cost. You can draw all types of class Diagrams, reverse code, generate code from diagrams and generate documentation. The UML CASE tool also provides abundant UML tutorials, UML interactive demonstrations and UML projects.

Feature List:
+Support UML version 2.1
+Business Workflow diagram
+ (New Feature)
+Handi-Selection (New Feature)
+Command-line operations (New Feature)
+User Interface Designer (Enhanced)
+Java Roundtrip engineering
+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
+Use Case Details Editor - An all-in-one environment for specifying a use cases details including general model specification and use case descriptions
+EJB Diagram - Visualize EJB systems
+EJB Code Generation
+Data flow diagram
+ORM support - generate Java objects from database
+Database generation - ERD to database tables
+Database reverse - existing DBMS to ERD
+Modeling collaboratively with VP Teamwork Server, CVS and Subversion (Enhanced)
+Report generator for generating documentation
+Automatic diagram layout
+Import/export XMI file
+Import Telelogic Rhapsody Project File (New Feature)
+Support Stored Procedure and Database Trigger (New Feature)
+Export diagrams to JPG, PNG, SVG, EMF, PDF
+Shape editor
+More...

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

Windows Platform:
+SDE for Microsoft Visual Studio
+More SDE... you can free download Visual Paradigm for UML (ME) for Java 6.1 now.