Given below is a class that represents a Book with three attributes: author, title and publishDate.

public class Book {

private String author, title;

private Date publishDate;

Book(String s, String r, Date v){

author = s; title = r; publishDate = v;

}

public String author(){return author;}

public String title(){return title;}

public Date publishDate (){return publishDate;}

public String toString(){return author+" "+title+" "+ publishDate;}

}

Your task is to write the following method for the Book class:

(a) equals, that returns true if two instances of the Book class have the same Author and Title.

(b) hashCode, that returns a hash code for an instance of the class.