Why can Java implement multiple interfaces?
A Java class can only extend one parent class. Multiple inheritance ( extends ) is not allowed. Interfaces are not classes, however, and a class can implement more than one interface. The parent interfaces are declared in a comma-separated list, after the implements keyword.
Why we use interface in Java and explain method to implement interface?
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 . Interfaces are used to implement abstraction.
Is it necessary to implement all methods of an interface in Java?
Must we implement all the methods in a class that implements an interface in Java? 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. Implement every method defined by the interface.
How are interfaces used in a Java program?
An interface can extends another interface or interfaces (more than one interface) . A class that implements interface must implements all the methods in interface. All the methods are public and abstract. And all the fields are public, static, and final. It is used to achieve multiple inheritance. It is used to achieve loose coupling.
Can a class implement both interfaces in the same class?
If both interfaces have a method of exactly the same name and signature, the implementing class can implement both interface methods with a single concrete method. However, if the semantic contracts of the two interface method are contradicting, you’ve pretty much lost; you cannot implement both interfaces in a single class then.
What happens if two methods have the same implementation in Java?
As far as the compiler is concerned, those two methods are identical. There will be one implementation of both. This isn’t a problem if the two methods are effectively identical, in that they should have the same implementation. If they are contractually different (as per the documentation for each interface), you’ll be in trouble.
How are interfaces used to provide total abstraction?
It is used to provide total abstraction. That means all the methods in an interface are declared with an empty body and are public and all fields are public, static and final by default. A class that implements an interface must implement all the methods declared in the interface. To implement interface use implements keyword.