Do URIs used in RDF need to be dereferenceable in Jena?

Question

I'm looking over the Jena tutorial, An Introduction to RDF and the Jena RDF API, and am specifically looking at Tutorial01.java. The PersonURI is very vague, as it is defined as:

static String personURI    = "http://somewhere/JohnSmith";

Does this URI need to dereferenceable? If so, do all RDF implementation require a web server? Lastly, what is served up at that URI if it does need to be dereferenced and returned?

Answer 1

No it does not. Actually, regardless of Jena, a URI does not have to be resolvable anyway. A URI is an identifier of an entity. A URL is always a URI. This does not mean that a URI is necessarily a URL.

Copying from the RDF primer:

As discussed in Section 2.1, the Web provides a general form of identifier, called the Uniform Resource Identifier (URI), for identifying (naming) resources on the Web. Unlike URLs, URIs are not limited to identifying things that have network locations, or use other computer access mechanisms.

Hope I helped!

Answer 2

It does not need to be resolvable.

That's good practice for publishing on the web but Jena does not look names up just because you use them.