After switch from 11g to 12c, I use Altova XMLSpy.
Here is a video saying how to do it:
https://www.youtube.com/watch?v=piVbWtChd6I
And one more nice feature - XSLT / XQuery Back-mapping in Altova XMLSpy:
https://www.youtube.com/watch?v=lK1EDLbxxyo