Yes, they are different. Otherwise the language designers wouldn't have provided both. I know two languages that separate classes and interfaces: Java and C#, mutated clone of Java. The designers created interfaces to avoid supporting multiple class inheritance. Most other languages support multiple class inheritance and consequently don't separate classes and interfaces.

Yes, they are different. Otherwise the language designers wouldn't have provided both. I know of two languages that separate classes and interfaces: Java and C#, mutant clone of Java. The designers created interfaces to avoid supporting multiple class inheritance. Most other languages support multiple class inheritance and consequently don't separate classes and interfaces.