Open Source Java UML Tools

PlantUml allows to quickly create some UML diagram using a simple textual description language.

Yaoqiang BPMN Editor is a graphical editor for business process diagrams, compliant with OMG specifications (BPMN 2.0 / DMN 1.1).

Tools to allow Z specifications to be written in Microsoft Word. Includes a unicode font for Z symbols. Provides: WYSIWYG editing fully integrated into Word; Typechecking using fuzz (for Spivey Z) or CZT (for ISO standard Z); Indexing and cross-referencing; Diagrams of specification structure; Conversion from Spivey to Standard Z- also available as a stand-alone program and Java class for non-windows users. See project website for details.

Design/Reverse Engineer/Generate Scripts/Compare Versions of all major databases with "Apricot DB" ERD- tool "Apricot DB" is a database tool for design and analysis of the relational database structure. It represents the DB- structure in the form of editable Entity/Relationship Diagrams (ERD). "Apricot DB" allows to perform reverse engineering on the existing database, as well as to create a new database structure from scratch. Allows to generate the essential DDL- scripts for CREATE/DROP/DELETE- operations based on the current ERD. "Apricot DB" supports two popular ERD notations: the "Crow's Foot" and "IDEF1x". The databases supported by Apricot DB: Oracle; SQL Server; MySQL; MariaDB; PostgreSQL; DB2/DB2 LUW; H2; SQLite Your feedback is appreciated.

Green, an Eclipse plugin, is an advanced yet simple UML class-diagram tool, developed primarily for student use. It does live round-tripping, so it's easy to move between diagram and code views. It's extensible: users can define their own relations

Takes in a simple text file and converts it into a UML diagram. Currently simple sequence diagrams are implemented. The diagramming space on Linux boxes isn't great and I wanted a way to quickly put together a sequence diagram.