Can I use PlantUML with Astah?
How to Install and Use the Astah PlantUML Plugin
Yes, Astah provides an official PlantUML Plugin that allows you to seamlessly bridge text-based modeling with Astah’s visual environment.
With this plugin installed, a new PlantUML View pane is added to your workspace.
You can write PlantUML text to generate live previews and import them directly into Astah as model elements, or conversely, export your existing Astah diagrams into PlantUML code.
You can find the currently-supported elements on Github ReadMe.