[hibernate-dev] Hibernate & Java 5 ?

Wed Dec 9 15:15:19 EST 2009

WRT backport and the use of backport-util-concurrent as a dependency,  
it would require people to add a new dependency which is not so fun on  
a micro release.
My 2c.

On 9 déc. 2009, at 16:58, Steve Ebersole wrote:

> I'm actually ok with just dropping 1.4 support for 3.5.
>
> If you are going to do it, I'd say that "dirty read" here is ok.  What
> I'd worry about though is concurrency issues like blocking (reads on
> unsynchronized maps can cause blocks iirc).
>
> As for backporting, well it depends, on a few things.  First, if you
> want it backported to version prior to 3.5 it will absolutely need  
> some
> form of 1.4 compatibility.  I think backport-util-concurrent, as you
> mention, is the best option.  Then its mostly a matter of how  
> disruptive
> the change is.
>
> On Wed, 2009-12-09 at 14:12 +0100, Alex Snaps wrote:
>> What about the dirty reads? Should I mark all getters as synchronized
>> methods, or just leave it as is? Not knowing how intensively these
>> getters are being called...
>> Btw, would this be backported into older 3.x releases as well?
>>
>> On Wed, Dec 9, 2009 at 1:39 PM, Emmanuel Bernard <emmanuel at hibernate.org 
>> > wrote:
>>> I don't think it's critical to backport this for 1.4 JDK users.  
>>> But if you want to spare cycles...
>>>
>>> On 9 déc. 2009, at 12:48, Alex Snaps wrote:
>>>
>>>> I have finished a first version of it all:
>>>> It is supporting both jdk 1.4 and 1.5+. So that if the
>>>> java.util.concurrent classes are present, it will use the new
>>>> ConcurrentStatisticsImpl, otherwise will fallback to the current
>>>> StatisticsImpl. As mentioned, I had to extract interfaces for
>>>> EntityStatistics, CollectionStatistics,  
>>>> SecondLevelCacheStatistics and
>>>> QueryStatistics.
>>>> Now, there is still the issue of the dirty reads within the current
>>>> StatisticsImpl. (no synchronization on read)...
>>>> What would you guys think of fixing these with the
>>>> backport-util-concurrent ? So that even the 1.4 jdk get better
>>>> concurrency on these...
>>>> That would include a new dependency... I'm also currently looking  
>>>> into
>>>> not including the deps, and using the same tricks as they are  
>>>> doing to
>>>> diminish contention...
>>>> Their AtomicLong relies on synchronization, but at least every stat
>>>> gets its own lock, versus everyone competing for the same one as  
>>>> it is
>>>> currently the case.
>>>> wdyt?
>>>>
>>>> On Tue, Dec 1, 2009 at 3:59 PM, Steve Ebersole  
>>>> <steve at hibernate.org> wrote:
>>>>> I guess I have just been waiting until we can actually leverage  
>>>>> 1.5
>>>>> features (ala utilize enums or expose generics/typing).  That  
>>>>> will not
>>>>> happen for 3.5.
>>>>>
>>>>> Now statistics are encapsulated behind a set of interfaces  
>>>>> (Statistics
>>>>> and StatisticsImplementor).  We could make this alterable like I  
>>>>> did for
>>>>> JDBC 3/4 based on the JVM.  That would mean reflection code  
>>>>> though.
>>>>>
>>>>> I do not actually know of any real cases of Hiberate being used  
>>>>> in 1.4
>>>>> environments today.  So maybe we can just make it 1.5 compatible.
>>>>>
>>>>> Votes?
>>>>>
>>>>>
>>>>> On Tue, 2009-12-01 at 14:38 +0100, Alex Snaps wrote:
>>>>>> We've been doing some improvement to the Hibernate statistics at
>>>>>> Terracotta, when we realized how much the synchronization on it  
>>>>>> was
>>>>>> impacting throughput in our tests.
>>>>>> That is work we wanted to contribute back to you guys, should
>>>>>> Hibernate Core be target at 1.5. As it seems that's not yet the  
>>>>>> case,
>>>>>> so there isn't much you guys will be able to do with these  
>>>>>> changes...
>>>>>> We discussed about that at Devoxx with Max and Emmanuel and  
>>>>>> thought it
>>>>>> was okay to have 1.5 impl. of the specs (java.util.concurrent  
>>>>>> based)
>>>>>> already. Apparently not :( What timeframe do you see 1.4  
>>>>>> support being
>>>>>> dropped?
>>>>>>
>>>>>> On Tue, Dec 1, 2009 at 1:44 PM, Steve Ebersole <steve at hibernate.org 
>>>>>> > wrote:
>>>>>>> I have issues reloading Maven-based projects in IntelliJ as  
>>>>>>> well.  I
>>>>>>> simply try to minimize the number of times I reload.
>>>>>>>
>>>>>>> Hibernate is *built* with JDK 1.5, but not all the modules are  
>>>>>>> 1.5
>>>>>>> compatible.
>>>>>>>
>>>>>>> What "statistics work" discussion?  I must have missed that.   
>>>>>>> But for
>>>>>>> sure the hibernate-core module should remain 1.4 compatible.   
>>>>>>> Dropping
>>>>>>> 1.4 support is on the roadmap, but not for 3.5
>>>>>>>
>>>>>>>
>>>>>>> On Tue, 2009-12-01 at 11:32 +0100, Alex Snaps wrote:
>>>>>>>> Hey,
>>>>>>>> Doing a svn update of the Hibernate trunk, I realized I  
>>>>>>>> probably had
>>>>>>>> changed the project to be Java5 manually as it reverted to 1.4
>>>>>>>> (because of some pom.xml change) in IntelliJ.
>>>>>>>> Talking to Max and Emmanuel at Devoxx I thought trunk was now  
>>>>>>>> to be
>>>>>>>> Java 5? Is this not the case after all, or are poms only  
>>>>>>>> update when
>>>>>>>> the first Java5 language/jdk feature sneaks in?
>>>>>>>> As discussed we discussed, all the statistics work heavily  
>>>>>>>> rely on
>>>>>>>> java.util.concurrent classes, so that is "more or less"  
>>>>>>>> important for
>>>>>>>> that patch...
>>>>>>>> Btw do you guys have a contributor agreement somewhere, I  
>>>>>>>> couldn't find it.
>>>>>>>> Thanks,
>>>>>>>> Alex
>>>>>>>>
>>>>>>> --
>>>>>>> Steve Ebersole <steve at hibernate.org>
>>>>>>> Hibernate.org
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>> --
>>>>> Steve Ebersole <steve at hibernate.org>
>>>>> Hibernate.org
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Alex Snaps <alex.snaps at gmail.com>
>>>> Software Engineer - Terracotta
>>>> http://twitter.com/alexsnaps
>>>> http://www.linkedin.com/in/alexsnaps
>>>>
>>>> _______________________________________________
>>>> hibernate-dev mailing list
>>>> hibernate-dev at lists.jboss.org
>>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>>>
>>>
>>
>>
>>
> -- 
> Steve Ebersole <steve at hibernate.org>
> Hibernate.org
>