When the UML-to-Java transformation generates classes, operations, and fields, it assigns the @generated tag to these elements. The next time that you run the transformation, the transformation overwrites these elements. When you delete elements from the source model and rerun the UML-to-Java transformation, the transformation deletes previously generated fields and methods that still have the @generated tag and that no longer have a corresponding source model element. However, for files that the transformation generates, you can specify whether or not to delete files.
To specify delete options for the UML-to-Java transformation output: