With inheritance of interface you inherit only the method declarations, not the implementation. So when you inherit interface, your new object exposes all of those methods declared in the subclass.

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

A controversial new proposal for .NET suggests the introduction of a limited form of multiple inheritance via abstract interfaces. This feature was inspired by Java’s default methods.

Neither of the two "big" programming languages to come out in the last few years, Java or C#, make use of multiple implementation inheritance, providing only interface inheritance.

Background In literature, one encounters the terms subclassing and implementation inheritance, among others, to refer to the use of inheritance as a means for code reuse. The terms subtyping, ...