Right joins are only unsupported in the JPA Criteria implementation in 5.x. In 6.0+ this is supported, but also in HQL since 5.x.
Note though that I would suggest you to use only a single kind of join if possible (i.e. left or right), as it might be very confusing when mixing join types. I personally only use left joins as I generally try to join from a “tree root down to leaf nodes”.