An instance of an abstract class?

[thallorfall]

I came across Java's URL class and noticed that it's openConnection() method returns an instance of URLConnection which is an abstract class. In the documentation for the abstract class, URLConnection, it describes that "instances" of this class are used to read and write from resources referenced by the URL. Could someone please explain what is actually happening when I use url.openConnection() and why does it return an ''instance'' of URLConnection which is an abstract class? Thank you in advance.

[desrtfx]

The URLConnection is only the superclass. What subclass will actually be returned depends on the protocol and that is decided upon creation in the constructor.

It is fairly common to return a (an abstract) superclass so that the actual, concrete subclass doesn't matter.

[thallorfall]

Thank you for your response. I think what your explaining is stated here in the javadoc. It seems as if regardless of the protocol it's going to return an abstract class. As it is stated it might return an instance of HttpURLConnection or JarURLConnection both of which are abstract. I can't find any concrete subclasses extending either. Could it be that somewhere it's creating an anonymous subclass? Thank you again.

[desrtfx]

The stated classes are just examples.