A description including images illustrating the problem have been posted here http://community.jaspersoft.com/questions/851263/jasperreports-603-broken-report
Looking at the source for JasperReports library 6.0.2 and comparing with 6.0.0 there seems to be some new code/classes related to the Barcode4j library. When update the .jar files used by my application http://www.commander4j.com and re-run the application the output shows that the size of the barcode generated is incorrect. I am not sure if this is due to some issue with stretch properties or the new library non picking up the barcode4j xml formatting file.
I have attached a PDF containing the contents of the url at the top of this post in case it is subsequently moved.
This problem has forced me to revert back to 6.0.0 and I cannot update until a workaround/fix is available. I have not been able to find any documentation on the properties of the Barcode4j integration to the JasperReports plugin to Eclipse Luna.
This application runs on any platform with Java 1.7 and was demonstrated to have a problem with a mysql database, although the problem is not database specific.