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Can we implement interface to another interface?
An interface can extend any number of interfaces but one interface cannot implement another interface, because if any interface is implemented then its methods must be defined and interface never has the definition of any method.
Is it necessary to implement all the methods of an interface while implementing the interface?
Yes, it is mandatory to implement all the methods in a class that implements an interface until and unless that class is declared as an abstract class. Declare the class as an abstract class, as a result, forces you to subclass the class (and implement the missing methods) before you can create any objects.
Can more than one class implement the same interface?
Yes multiple classes can implement one interface irrespective of being in the same program or different. There is no such restriction. Interface only defines the common methods that should be included in the Implementation classes.
Which one is used to implement the interface?
To implement interface use implements keyword. Why do we use interface ? It is used to achieve total abstraction. Since java does not support multiple inheritance in case of class, but by using interface it can achieve multiple inheritance .
What does it mean to implement an interface?
An Interface is a specification of functionality that a class MUST implement. When you implement an interface, you are specifying to any consumers of your class that you supply the functionality defined in the given Interface.
What happens when two classes implement the same interface?
A class implementation of a method takes precedence over a default method. So, if the class already has the same method as an Interface, then the default method from the implemented Interface does not take effect. However, if two interfaces implement the same default method, then there is a conflict.
What’s the difference between an interface and an implements?
Implements denotes defining an implementation for the methods of an interface. However interfaces have no implementation so that’s not possible. An interface can however extend another interface, which means it can add more methods and inherit its type.
Can you instantiate an interface without its implementation?
No You can’t call it, You will have to provide its implementation atleast Further to call method you will need an object. you can’t instantiate interface without its implementation provided The interface is just a definition of methods without implementation. If you are not implementing the methods what will they do when you call them?
Is it possible to implement an interface in an abstract class?
I googled it and I found this: implements denotes defining an implementation for the methods of an interface. However interfaces have no implementation so that’s not possible. However, interface is an 100% abstract class, and an abstract class can implement interfaces (100% abstract class) without implement its methods.
Can a method which is inside an interface without..?
But in order to execute it, you will need to implement it somewhere, because interface just describes how something behaves but does not provide the actual behaviour (i.e. does not implement it). Now call savePerson on p. You are implementing IPerson without creating a separate class.