Java 8 Lamda expression : with return Type with Argument

interface Messenger{
public String printMessage(String value);
}

public class LamdaExpressionExamples {

public static void main(String[] args) {

Messenger obj =  (arg) -> {
return " hello "+arg;
};
//or
//Messenger obj = (arg) -> " hello "+arg;

String message = obj.printMessage("Good Morning");
System.out.println(message);
}
}
Output
hello Good Morning