Astah supports modeling in Java, C++, and C#. If you are modeling in Java, set so in Astah first.
You can set Java as your programming language to Astah by default from [Tools] – [System Properties ] – [Project].
You can import Java source code and generate Class diagrams with the models.
You can auto-create a Class diagram with imported models.
After generating a diagram, you can auto-layout from [Alignment] menu.
Astah’s Easy Code Reverse Plug-in is the easiest way to reverse source code from Github, Bitbucket, and Gooogle Project Hosting into a UML class diagram just by drag-and-dropping the URL a repository or the .java source code files directly on to Astah!
“Export Java” is used to generate Java Skeleton Code from selected Diagram Elements. The Definitions of Classes and Operations are exported as Documentation Comments.