I am fairly new java  Technology, but I will try to help.

I did not find a direct creation mechanism for a word  document in the API's, but
I did finf the Class RTFEditorKit.

java.lang.Object
javax.swing.text.EditorKit
javax.swing.text.DefaultEditorKit
javax.swing.text.StyleEditorKit
javax.swing.text.rtf.RTFEditorKit

I think that this will give you a lot of Inner classes to use which could be
used to dynamically  create an RTF document  that Microsoft word editors could
then open.