Does this mean multiple inheritance?
For interfaces, yes, but not classes. Usually these are classes that people think of, since only classes can have fields and constructors. This is no different from Java 1.0.
should the return type be a co-option of the else type to compile the problem, does that mean it still does not support multiple inheritance?
The need for a covariant type of return is not related to the presence of multiple inheritance or not.
Is it possible to say that java supports multiple inheritance?
For interfaces, yes.
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