| Note that Interfaces often play a software engineering as opposed to required functional role |
| For instance, the printable interface (which is fictitious and not part of current Java release) establishs that any class implementing it can be "printed" with a standard method -- "print" |
| 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: |