In Astah Professional, you can easily import java code and create models (packages, classes, etc.) in the project.
Go to [Tool] - [Java] - [Import Java] in the main menu
- Select java files in the [Select Java File] dialog box.
Specify the character you want to use to import .java files from the dropdown list of [Charset of imported files]
- Models (packages, classes, etc.) are created
- Auto create a class diagram from the popup menu on the structure tree