we are currently using hibernate 3.3.2 and spring 2.5.6. we were using xdoclet to generate our hibernate cfg files from our java files. we switched to using annotations. nothing else was changed in our codebase. we have seen a performance degradation of at list 4 fold and in some cases 10 fold. we have also noticed that we need to allocate significantly from ram to the jre to even run the tests.

has anyone else experienced this?

reading the annotations has an overhead, so you might theoretically experience a slower startup - never noticed though - but it shouldn't be slower after the SessionFactory is initialized.
Do you have some numbers? Can you verify there's slowdown even during usage (not during startup) ?

startup is definitely slower, but only a little. it's runtime that is slower.

we have verified that we seem to be getting roughly the same sql across our tests. (we have some places where we didn't set the fetch correctly so we are getting a little more sql but only 2-3% more)

we have noticed a lot of 'pausing'. a whole batch of tests will run, then one will just site for many seconds, then it all starts up again.

as a test i ran with hibernate 3.5.3 and spring 3.0.x and it was better, but still 3 times slower than 3.3.2 and 2.5.6 without annotations.

So there might be something going wrong there, but you don't have a proof that's the fact you switched to annotations right?
You should try using the exact same versions and queries.

Might be offtopic, but I'm interested to hear about the performance difference between hibernate 3.3.2 and 3.5.3 - tough it doesn't seem related to using/not using annotations.

yes i have proof. same exact code base. in one case i use AnnotationConfiguration to configure hibernate and in the other i use the basic Configuration class to configure hibernate from xml mapping files. at least a 10x performance degradation.

i have even run tests where i take spring out of the equation and just create hibernate sessions directly.

i have also tried running with java6 instead of our default of java5

i am either doing something completely wrong, or there aren't a lot of people that have migrated from xml config to annotations, or other people would have had the same issues.

if you could post this test we might be able to fix it