Files created with CreatePDFA.java are not PDF/A-1b

Reported first by Julien on the user mailing list:

The file/tmp/test.pdf is not valid, error(s) :
7.1 : Error on MetaData, xmp should start with a processing instruction

It is even worse in 2.0:

2.1.4 : Invalid graphics object, DestOutputProfile isn't a valid ICCProfile: Invalid ICC Profile Data
3.1.5 : Invalid Font definition, ArialMT: Symbolic TrueType font has more than one 'cmap' entry
3.1.5 : Invalid Font definition, ArialMT: The Encoding should be missing for the Symbolic TTF
7.1 : Error on MetaData, xmp should start with a processing instruction