ok, so, ..stuff..
part of my JPQL contained an inner join to other table. Even through in SELECT there were selected fields just from one table, which was used as type - Timetable
, Eclipslink was unable to determine if this fields are part of that entity and instead of returning list of defined entity returned list of Object[]
.
So in conclusion: Use @OneToMany/@ManyToOne mappings (or flat table design) and query just for ONE table in your JPQL to be able to typize returned entities.