The "No java runtime was found" warning disappeared. Likely corrected upstream since 2016.
I realise today that installing libbatik-java and libavalon-framework-java packages in Ubuntu makes the two other warnings disappear too.
I suppose that these warnings a related to the contents of the schema and that they are not present for everybody, but this is not easy to understand for an occasional, non professional user of jing and of RelaxNG.
The "No java runtime was found" warning disappeared. Likely corrected upstream since 2016.
I realise today that installing libbatik-java and libavalon- framework- java packages in Ubuntu makes the two other warnings disappear too.
I suppose that these warnings a related to the contents of the schema and that they are not present for everybody, but this is not easy to understand for an occasional, non professional user of jing and of RelaxNG.