Systems often start (or “launch”) daemons at boot time: they often serve the function of responding to network requests, hardware activity, or other programs by performing some task. Daemons can also configure hardware (like devfsd on some Linux systems), run scheduled tasks (like cron), and perform a variety of other tasks.
There are plenty of deamon utilities available. Whois can be used to query the whois record for a registered domain name. Looking glass can be used to view BGP routing information and traceroute will show ip routing. Most of these are available as a free download.
A deamon is also a spirit, or immaterial being, holding a middle place between men and deities in pagan mythology.
A Java Daemon is made of 2 parts. One written in C that makes the interface to the operating system and the other in Java that provides the Daemon API.
Non Unix operating system have different ways of allowing user independent tasks to run. Microsoft based systems call such processes services. They run independently of user control but can still be administered through Computer Management via the Control Panel.