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Can multiple classes implement the same interface Java?
Since java class can implement multiple interfaces and each interface can define default method with same method signature, therefore, the inherited methods can conflict with each other. A class can implement multiple interfaces and many classes can implement the same interface.
Can many classes can 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 is the relationship between interface and classes?
Differences between a Class and an Interface:
| Class | Interface |
|---|---|
| It can be inherit another class. | It cannot inherit a class. |
| It can be inherited by another class using the keyword ‘extends’. | It can be inherited by a class by using the keyword ‘implements’ and it can be inherited by an interface using the keyword ‘extends’. |
Can we extend two classes in Java?
Classes in Java support single inheritance; the ArmoredCar class can’t extend multiple classes. Also, note that in the absence of an extends keyword, a class implicitly inherits class java. lang. Object.
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 are the benefits of composition in Java?
Composition allows us to reuse the code. In Java, we can use multiple Inheritance by using the composition concept. The Composition provides better test-ability of a class. Composition allows us to easily replace the composed class implementation with a better and improved version.
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 do you define an instance of an interface?
You define the instance of an interface by executing the constructor of a concrete class that implements the interface. interface cannot have body/definition for the method. All the methods are abstract. You cannot define method body, hence you cannot call any method from interface. Not the answer you’re looking for?