atom feed3 messages in org.apache.incubator.jena-devWhen should we use Java's UUID, and w...
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Bruno P. KinoshitaAug 11, 2018 2:47 am 
Andy SeaborneAug 11, 2018 1:49 pm 
Bruno P. KinoshitaAug 11, 2018 2:39 pm 
Subject:When should we use Java's UUID, and when should we use Jena's JenaUUIDs?
From:Bruno P. Kinoshita (
Date:Aug 11, 2018 2:47:49 am


Regarding changes in Jena code, not talking about SPARQL uuid or struuid
functions... Does anyone here know when one would use Java's UUID in Jena over
JenaUUID implementations, or vice versa?

I wrote one of those brain-dump posts, with several notes to myself, about what
happens when you upload a dataset in Fuseki. Ended up with a post-it to check
out JenaUUID.

Today I had some spare time, and tried learning how it works [1], from what I
understood, we have a Version 1 (UUID_V1) and a Version 4 UUID (UUID_V4)
implementations in Jena, where version 4 is compatible with Java's UUID (but
with a stronger seed for multiple JVM's?).

But in certain parts of the code we use Java's UUID. The transaction ID's are
either sequential or JenaUUID. But blank node ID's are either sequential or
Java's UUID.

Just so I learn (and satisfy my curiosity), in case I ever have to touch code
that involves UUID's in Jena... is there a rule for when to choose one over the

Thank you! Bruno