Your machine needs to be able to resolve host names. This is typically done with a system called DNS. Your machine acts as a DNS client, making requests to a configured DNS server for resolution of host names, such as "www.ibm.com".
Nothing to do Java, and certainly not advanced. Google is your point of reference.
Tony Morris Java Q&A (FAQ, Trivia)
That's a very big dog. I think I want to go home now and hug this tiny ad: