I just came across a link which talks about the licensing part for using the Adobe fonts in Acrobat Reader PDF:
"Note: The font software contained in this package is being licensed to you solely for use with Adobe (R) Acrobat (R) Reader (R) software ("Acrobat Reader") and is subject to the terms and conditions of the electronic End-User License Agreement accompanying Acrobat Reader."
This explains why iText doesn't ever embed a CJK font in the PDF file. These fonts have to be downloaded and used in the context of Adobe Reader; you can not use them with iText to produce a PDF document that has these fonts embedded (as you would do with other fonts) so that they can be viewed in other readers; unless you have a license from Adobe to use these fonts.
I understood we can't use the Adobe fonts in Acrobat Reader without license, but how about using the Google NOTO fonts in Acrobat Reader? Do we need the license for this?