This is a bugfix release to address mainly the following things:
#1191 race conditions in data loader dispatching
#1182 fix null element
#1150 class cast exception in schema generation
#1142 validate input variables
#1113 npe in field tracking during dispatch
#1159 fix json encoding of values
See https://github.com/graphql-java/graphql-java/pulls?q=is%3Apr+milestone%3A9.3