Hi,
It is possible to query data into maps or custom value objects with use of HQL, to return only subset of information rather than to load whole entity(ies).

I wonder, if I use 'select new map(..)' - does it really slower than 'select new SomeValueObject(...)' ? With use of maps I have flexibility in returing dynamic number of fields, while with custom value object, i will be limited with properties defined there and for every new subset of them i will need to create correspondent constructure with parameters.

Did anyway profile both types of queries ?

they both work the same. the only diff is one instantiates a map and put stuff in it the other one instantiates a pojo and put stuff in that.

I was wondering if some better perfomance can be gained from use of POJO, since in this case all Hibernate need to do is to call Constructor(param1, param2, etc.) rather than iteration thru each column and call map.out("field1", field1)
If it is not sagnificant,than it makes sense to keep using maps as more flexiable solution

test it for your usage scenario. too many factors to say for sure.