Java 8 Lamda expression : with return Type no Argument

interface Messenger{
public String printMessage();
}

public class LamdaExpressionExamples {

public static void main(String[] args) {

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

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