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From Andy Seaborne <>
Subject Re: Jena and Java version : drop Java 1.5?
Date Wed, 03 Aug 2011 13:15:19 GMT

On 03/08/11 13:40, Marco Neumann wrote:
> from my observations I can say that quite a number of production
> systems still come with Java 5 as default JVMs. So I would at least
> provide a Java5 compatible zip as a download for major milestones for
> the next 2 years or so.

Useful information - can we quantify this?  Especially production system 
that might run semantic web software.  There are likely lots of old Java 
versions still running, but those systems are unlikely to run whacky 
semweb stuff.

There is a not-insubstantial base of old Jena installations.  Really, 
really old ones do occasionally turn up - but they usually will want 
backporting patches and not a whole new version.  And they have the 
source code ... :-)

> That said I've switched to JVM6 64bit now on all lotico sites and am
> very happy with the robustness, though I do not see any significant
> performance benefits for<100M stores.
> I really would like to see native result set caching sooner than
> later. Any plans for such opulence? :-)


> On Wed, Aug 3, 2011 at 8:03 AM, Andy Seaborne
> <>  wrote:
>> On 03/08/11 12:12, Damian Steer wrote:
>>> On 3 Aug 2011, at 11:42, Andy Seaborne wrote:
>>>> Java7 is out. [*] [+]
>>>> We have in the past had a policy of supporting "two major Java
>>>> versions".  I think all the released modules are Java 1.5 except
>>>> Fuseki (which isn't yet a library anyway) and TxTDB is Java6, for
>>>> the more complete library and better conncurrency implementation.
>>> Remind me, what are the differences here? What are you using? The
>>> only thing I trip up on is String#isEmpty (yes, it took them 6
>>> revisions to add this).
>> Bug fixes :-) is the biggest item.  Java6 seems to have a certain amount of
>> "Java 1.5, fixed" about it.
>> Deque's and BlockingDeque; e.g. Stack =>  ArrayDeque
>> I also use @Override on interface methods.  The odd method like
>> String.isEmpty.
>>>> I propose we set the supported Java version to Java6.
>>> +1. I'd normally suggest some sort of relaxation period (7 is very
>>> fresh after all), but 6 has been around for an awfully long time now.
>>> Here at Bristol University many production systems are using 6, and
>>> I'd class them as fairly conservative.
>> Yes - my sense is that Java6 is the norm, both from bug fix POV and because
>> Java 1.5 is EOL.  (We/Epimorphics had two different Java-ism in one day only
>> this week, and this was between builds of 1.6.0 and/or the kernel.)
>> I'm not expecting fast Java7 uptake for deployed systems.  I don't know how
>> much FUD there is and how much real issues; I have no real need to rush to
>> Java7 and a lot of other things to do.
>> It's more that the Java7 release reminded me of the "two version" policy.
>>   Until Java7 hits the Ubuntu repos, I'm not going to install it.  Fork/join
>> is interesting ... but Scala is more interesting.
>>> Damian
>>         Andy

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