UUID : Java Glossary

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UUID
UUID stands for Universally Unique Identifier. It is not in theory completely unique, but in practice, it is.
// generate a 128-bit high quality random number, almost certainly unique
import java.util.UUID;

// ...

UUID u = UUID.randomUUID();
System.out.println( u );
// prints something like 2867ac57-f109-470c-abec-124deea787e1
// timelow - timemid - timehigh+ver - variant+sequence - node
// The fields have nothing to do with time in this type 4 UUID.
// They only have literal time meaning for a type 1 UUID.
will generate a 128-bit random number using SecureRandom. The intent is to create unique identifiers for things without having to have a central agent handing out numbers.

Learning More

Sun’s Javadoc on the UUID class : available:

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