Create a GUID in Java

It depends what kind of UUID you want.

• The standard Java UUID class generates Version 4 (random) UUIDs. (UPDATE - Version 3 (name) UUIDs can also be generated.) It can also handle other variants, though it cannot generate them. (In this case, "handle" means construct UUID instances from long, byte[] or String representations, and provide some appropriate accessors.)

• The Java UUID Generator (JUG) implementation purports to support "all 3 'official' types of UUID as defined by RFC-4122" ... though the RFC actually defines 4 types and mentions a 5th type.

For more information on UUID types and variants, there is a good summary in Wikipedia, and the gory details are in RFC 4122 and the other specifications.

java.util.UUID.randomUUID();

Have a look at the UUID class bundled with Java 5 and later.

For example:

• If you want a random UUID you can use the randomUUID method.
• If you want a UUID initialized to a specific value you can use the UUID constructor or the fromString method.

Just to extend Mark Byers's answer with an example:

import java.util.UUID;

public class RandomStringUUID {
    public static void main(String[] args) {
        UUID uuid = UUID.randomUUID();
        System.out.println("UUID=" + uuid.toString() );
    }
}