Experimentation shows what the methods return, but the API comments could
provide the needed information. To wit:

Given URL url = new URL("http://foo/bar/baz.html");

url.getRef() => null
url.getPath() => /bar/baz.html
url.getFile() => /bar/baz.html
url.getProtocol() => http
url.getPort() => -1
url.getAuthority() => foo
url.toExternalForm() => http://foo/bar/baz.html

The comments currently say nothing. The getPath() method, for instance, says
"returns the path part of the URL", but that comment does nothing to help the
user understand what the path part *is*.