JAVA INTERFACE VS ABSTRACT CLASSES FULL
JAVA INTERFACE VS ABSTRACT CLASSES CODE

Abstract classes can have methods with implementation whereas interface provides absolute abstraction and can’t have any method implementations.

Subclasses use extends keyword to extend an abstract class and they need to provide implementation of all the declared methods in the abstract class unless the subclass is also an abstract class whereas subclasses use implements keyword to implement interfaces and should provide implementation for all the methods declared in the interface.

abstract keyword is used to create an abstract class and it can be used with methods also whereas interface keyword is used to create interface and it can’t be used with methods.

Difference between Abstract Class and Interface

A class implementing an interface must provide implementation for all of its method unless it’s an abstract class.ģ.

implements keyword is used by classes to implement an interface.

Java provides multiple inheritance in interfaces, what is means is that an interface can extend multiple interfaces.

An interface can’t extend any class but it can extend another interface.

By default interface methods are implicitly abstract and public, it makes total sense because the method don’t have body and so that subclasses can provide the method implementation.

By default any attribute of interface is public, static and final, so we don’t need to provide access modifiers to the attributes but if we do, compiler doesn’t complain about it either.

Interfaces can’t have constructors because we can’t instantiate them and interfaces can’t have a method with body.

Interface provides absolute abstraction, no method implementations.

We can’t instantiate an interface in java.

JAVA INTERFACE VS ABSTRACT CLASSES CODE

interface is the code that is used to create an interface in java.area ()) Ģ.2 Important Points about Interface in Java area ()) // switching from one implementation to another easily shape = new Rectangle ( 2, 8 ) shape. programming for interfaces not implementation Shape shape = new Circle ( 5 ) shape. Java interface is also used to define the contract for the subclasses to implement. Interface in java provide a way to achieve abstraction. We can run abstract class in java like any other class if it has main() method.Java Abstract class is used to provide common method implementation to all the subclasses or to provide default implementation.Java Abstract class can implement interfaces without even providing the implementation of interface methods.Static methods and default methods in interfaces are added in Java 8, for more details read Java 8 interface changes. All the methods in an interface are implicitly abstract unless the interface methods are static or default.The subclass of abstract class in java must implement all the abstract methods unless the subclass is also an abstract class.If abstract class doesn’t have any method implementation, its better to use interface because java doesn’t support multiple class inheritance.We can mark a class as abstract even if it doesn’t declare any abstract methods. It’s not necessary for an abstract class to have abstract method.If a class have abstract methods, then the class should also be abstract using abstract keyword, else it will not compile.We can use abstract keyword to create an abstract method, an abstract method doesn’t have body.Abstract class in java can’t be instantiated.abstract keyword is used to create an abstract class in java.area ()) ġ.2 Important Points about Interface in Java area ()) // switching from one implementation to another easily shape = new RectangleImp ( 2, 8 ) shape.

programming for interfaces not implementation BaseShape shape = new CircleImp ( 5 ) shape.

JAVA INTERFACE VS ABSTRACT CLASSES FULL

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Java interface vs abstract classes