Simple Workflow is a Java workflow engine that is really simple to use.
- Simple to use (need to call only 2 methods and implement 1 interface)
- Written in Java 7
- Uses a simple domain language to describe workflows
- Can be used with any storage backend (Sql, NoSql, File, etc.)
- Can be used with any frontend
- High level of backend/frontend abstraction
Simple Workflow is free and available here