Before jumping into the classes that are provided by the Java core API for dealing with URLs and the Web, you need to understand what is being referred to as URLs.
The primary classification of URLs is the scheme, which usually corresponds to an application protocol. Schemes include HTTP, FTP, Telnet, and Gopher. The rest of the URL syntax is in a format that depends on the scheme. A colon separates these two portions of information:
Thus, while mailto:email@example.com indicates "send mail to user 'chuckcavaness'at the machine yahoo.com," ftp://firstname.lastname@example.org means "open an FTP connection to foobar.org and log in as user chuckcavaness."
Although IP addresses uniquely ...