Is intreface inherits Object class, how can we able to access the methods of object class through a interface type reference

No Interface does not inherits Object class,but it provide accessibility to all methods of Object class. 
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 corresponding to each public instance method declared in Object, . 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.

Now it is clear that all superinterface have abstract member method corresponding to each public instance method declared in Object .