Default Methods inwards Interface, Multiple Inheritance as well as Diamond Problem inwards Java 8

Ever since Java 8 introduced default in addition to static methods inwards JDK 8, it's acquire possible to define non-abstract methods inwards interfaces in addition to since inwards Java ane degree tin implement multiple interfaces in addition to because in that place tin last concrete methods inwards interfaces, the diamond work surfaced again. What volition tumble out if ii interface has methods o the same elevate in addition to a Java degree inherit from it? Many Java programmer too asks me the inquiry that, is Java 8 is too supporting multiple inheritances of classes, equally it seems because interface amongst methods is similar to abstract degree or inwards that whatever class. Well, it’s not.

Multiple inheritances of classes is non supported inwards Java 8, instead compiler volition practise additional checks to avoid ambiguity inwards calling default methods in addition to Diamond problem, which could come upwardly if a degree implements ii interface which contains same default methods equally shown inwards the next example, it volition non compile inwards Java 8, because of ambiguity inwards calling default method write() from a class, which extends both Poet in addition to Writer interface.

interface Poet {     default void write() {         System.out.println("Poet's default method");     } }  interface Writer {     default void write() {         System.out.println("Writer's default method");     } }  public class Multitalented implements Poet, Writer{         public static void main(String args[]){         Multitalented toilet = new Multitalented();         john.write();  // which write method to call, from Poet                        // or, from Writer     } }  Output: Compile Time Error : class Multitalented inherits unrelated defaults for write() from types Poet and Writer

In lodge to solve this error, yous demand to override the write() method inwards your implementation degree i.e. degree Multitalented here, this volition take the ambiguity, making the compiler happy plenty to compile this class.

public class Multitalented implements Poet, Writer{         @Override     public void write(){         System.out.println("Writing stories immediately days");     }         public static void main(String args[]){         Multitalented toilet = new Multitalented();         john.write();  // This volition telephone telephone Multitalented#write() method     } } Output: Writing stories immediately days

So until yous don't practise ambiguity past times using default methods on interfaces, yous are fine to role it. If it creates ambiguity, the compiler volition warning yous past times throwing compile fourth dimension mistake "inherits unrelated defaults".

Further Reading
What's New inwards Java 8
Java SE 8 for Really Impatient
From Collections to Streams inwards Java 8 Using Lambda Expressions

Related Java 8 Tutorials
If yous are interested inwards learning to a greater extent than close novel features of Java 8, hither are my before articles roofing around of the of import concepts of Java 8:

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