Difference Between URL, URI and URN in Java

URI stands for Uniform Resource Identifier.URI is a sequence of characters used to identify resource location or a name or both over the World Wide Web. A URI can be further classified as a locator, a name, or both.

Syntax of URI: Starts with a scheme followed by a colon character, and then by a scheme-specific part. 

The most popular URI schemes, are HTTP, HTTPS, and FTP.

URL stands for Uniform Resource Location.URL is a subset of URI that describes the network address or location where the source is available.URL begins with the name of the protocol to be used for accessing the resource and then a specific resource location. URLs build on the Domain Name Service (DNS) to address hosts symbolically and use a file-path-like syntax to identify specific resources at a given host. For this reason, mapping URLs to physical resources is straightforward and is implemented by various Web browsers.

URN stands for Uniform Resource Name. It is a URI that uses a URN scheme. 

“urn” scheme: It is followed by a namespace identifier, followed by a colon, followed by namespace specific string

URN does not imply the availability of the identified resource.URNs are location-independent resource identifiers and are designed to make it easy to map other namespaces into URN space.

No	URI	URL	URN
1	URI stands for Uniform Resource Identifier	URL stands for Uniform Resource Location	URN stands for Uniform Resource Name
2	URI is a superset of URL & URN	URL is a subset of the Uniform Resource	URN  is a subset of the Uniform Resource.
3	It used to identify a resource on the internet either by location or a name or both	It is used to identify a resource on the internet either by location	It uniquely identifies the resource by name
4	URI is not always a URL	All URLs are URIs	All URNs are URIs
5	URI includes components like scheme, authority, path, query, etc.	URL includes protocol,domain,path,hash,query,string etc	URN does not include any component
6	Example: https://www.geeksforgeeks.org/setting-environment-java/?ref=lbp	Example: https%3A%2F%2Fwww.geeksforgeeks.org%2Fsetting-environment-java%2F%3Fref%3Dlbp	Example: setting up the environment in java

Here is a diagram that shows the relationship between URL, URI, URN: