Arrrgh! Do you smell that design flaw? Why would a Book be responsible for knowing if it was overdue or not?
Earlier i tried the same but i found it is bad so i change this responsibility to the Library. I also tried to do this using Java 8 lambdas but
could not succeed to come with this simple as you mentioned so i moved back to older style for sake of readability.
Yup, we should give correct good name. I am still doing small small mistakes. Thanks for pointing that. I have never thought about this