Wenity is a multi-platform Zenity clone that helps (shell) script writers to interact with their users through various types of GUI dialogs. Scripts call Wenity and receive the user's selection in the exit code/response file. It supports any operating system with Java and a GUI installed, supports complex return types by using response files, and has a modular architecture supporting different functions: simple dialogs (user input, information, question, error/warning), progress indicator dialogs, system tray notifications, file choosers, and file viewers (text and HTML).
Simple Workflow is a workflow engine. It is simple to use (you need to call only two methods and implement one 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, and has a high level of backend/frontend abstraction.