Comment 5 for bug 628731

They have a different purpose

querydsl-apt-1.9.3.jar - contains all the annotation processors for Querydsl
querydsl-hql-1.9.3-apt.jar - contains only the APT configuration (via META-INF/services) for the Querydsl HQL module

So if you use an explicit APT configuration where you specify the annotation processor in the javac command, you don't need the second jar