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Java 8 - Functions - Functional Interface





  • All Java functions implement the FunctionalInterface interface.
  • A functional interface must contain exactly one abstract method declaration, but any number of default and static methods.
  • The @FunctionalInterface annotation can be omitted when creating a functional interface.


@Slf4j
public class FunctionalInterface_ {

   @FunctionalInterface
   interface Dog {
     String bark(Person person);
   }

   public static void main(String[] args) {
     Dog dog = person -> "Bark at " + person.getFirstName();

     log.info(dog.bark(new Person("Tom", "Smith")));
   }

}

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