import org.junit.Test;

import java.util.function.Consumer;

// *** The point of lambda expression relating to functional interface is the lambda EXPRESSION

// is defining the single method accept() method for Consumer<T>, inside the functional

// interface

public class ConsumerTest {

@FunctionalInterface

interface TestInterface {

public void someMethod();

}

// Using custom functional interface TestInterface

@Test

public void consumerTestMethod1() {

// lambda expression defines what TestInterface functional interface's someMethod() does

TestInterface tI;

tI = () -> {

System.out.println("hi");

};

tI.someMethod();

}

// Using built-in functional interface Consumer<T>

@Test

public void consumerTestMethod2() {

// lambda expression defines what Consumer<T> functional interface's accept() does

Consumer<String> consumer;

consumer = a -> {

System.out.println(a);

};

consumer.accept("this will be printed per lambda expression defined");

}

}