Java’s interface language feature confuses many Java newbies. Many mistakenly assume that interfaces only sidestep Java’s failure to support multiple implementation inheritance. In reality ...

You can use multiple inheritance with interfaces, however. The difference between a class and an interface, in this case, is that interfaces don’t keep state.

A method might accept a specific type and its subclasses, but you want to restrict usage to a select few implementations of your own design. Java's open inheritance model can feel like an open ...