Note that Interfaces often play a software engineering as opposed to required functional role |
Note that Interfaces are not significantly used in current Java release where perhaps there are 15 times as many class definitions as interface definitions |
Two examples are Runnable and Cloneable both of which extend Object class -- note interfaces like classes can extend existing classes. |
The Runnable Interface has one method run() which must always be overwritten and is used to indicate that class with this interface can use threads without being a subclass of Thread. Applets must use Runnable if they need explicit threads because they explicitly are a subclass of panel and as no multiple inheritance, one cannot be a subclass of two classes |