There are several classes of UUID, so it depends a little on what the call to com.eaio.uuid.UUID() is doing. In general you will be ok.
In general you can assume it's unique, however version 1 time UUID's may not be. As they contain a time component and the machine mac address, which is sometimes zero'd out so you can reproduce a UUID for a specific time. See http://en.wikipedia.org/wiki/Universally_unique_identifier#Version_1_.28MAC_address.29 and http://wiki.apache.org/cassandra/FAQ#working_with_timeuuid_in_java Hope that helps. ----------------- Aaron Morton Freelance Cassandra Developer New Zealand @aaronmorton http://www.thelastpickle.com On 4/01/2013, at 2:26 AM, "Hiller, Dean" <dean.hil...@nrel.gov> wrote: > Another option is PlayOrm UniqueKeyGenerator.generateKey(). While it is not > returning a UUID, it does return a unique key for a specific cluster that is > nice and short too. > > Dean > > From: Baskar Sikkayan <techba...@gmail.com<mailto:techba...@gmail.com>> > Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" > <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> > Date: Thursday, January 3, 2013 3:00 AM > To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" > <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> > Subject: UUID - Java > > Hi, > I use the following code to generate the primary key. > > public static java.util.UUID getTimeUUID() { > > return java.util.UUID.fromString(new com.eaio.uuid.UUID().toString()); > > } > > Is this the correct approach? > > Do let me know if there i any better approach which guarantees no conflicts. > > Thanks, > Baskar.S