Do interface really extends the member of Object class?

To know this, we'll have to know about the members of  interface.

Interface Members:

The members of an interface are:
• Those members declared in the interface.
• Those members inherited from direct superinterfaces.
• If an interface has no direct superinterfaces, then the interface implicitly declares
a public abstract member method m with signature s, return type r, and throws
clause t corresponding to each public instance method m with signature s, return
type r, and throws clause t declared in Object, unless a method with the same
signature, same return type, and a compatible throws clause is explicitly declared
by the interface.
It is a compile-time error if the interface explicitly declares such a method m in
the case where m is declared to be final in Object.
It follows that is a compile-time error if the interface declares a method with a
signature that is override-equivalent to a public method of Object, but
has a different return type or incompatible throws clause.