A 16-bit character set defined by ISO 10646. See also ASCII. All source code in the Java programming environment is written in Unicode.
Uniform Resource Identifier. A compact string of characters for identifying an abstract or physical resource. A URI is either a URL or a URN. URLs and URNs are concrete entities that actually exist; A URI is an abstract super class.
Uniform Resource Locator. A standard for writing a text reference to an arbitrary piece of data in the WWW. A URL looks like "protocol://host/localinfo" where protocol specifies a protocol to use to fetch the object (like HTTP or FTP), host specifies the Internet name of the host on which to find it, and localinfo is a string (often a file name) passed to the protocol handler on the remote host.
Uniform Resource Name. A unique identifier that identifies an entity, but doesn't tell where it is located. A system can use a URN to look up an entity locally before trying to find it on the Web. It also allows the Web location to change, while still allowing the entity to be found.