Hibernate version: 2.1.6

Hi,

perhaps a stupid question and i know i've read something about it somewhere .. either in HiA or in the ReferenceDoc but i'm not able to find it again ... therefore it would be creat if someone can give me a tip ...

I know what the flag 'mutable=false' means concerning a class-mapping. I can change my object, but the changes won't get persisted to db ...

Writing a UserType, i can set 'mutable', too. But a 'immutable' Type will still be changed in DB (see IntegerType).

In HiA i've only (re-) found something like 'Hibernate can make some performance optimazions for immutable types...'.

I have a brief understanding what 'mutable' means in that case ... but it would be great if someone could write 1 or 2 sentences about it ... or say 'rtfm at page xyz' ...

When do i use 'mutable=true' and when 'mutable=false' in a UserType?

thx!
curio

Mutable means that a objects "inner things" can change without the object reference itself changing. For example a String object is immutable:

String s = "Test"
s1 = s.substring(3)
s1 =! s

e.g. the object "value" can never change as long as it is the same object. A Date however is mutable:

Date d = new Date(13,3,1998)
d.setYear(1997)

The d-reference is still the same, even though the object has now a different "value".

big thanks michael!

i don't know how to say that in english ... but i was completly ''standing on the line'' ... thanks for pushing :)

gtx
curio