Book.java

package tutorialquestions.question7206;

public class Book {

 private final int isbn;
 private String title;

 Book(int isbn, String title) {
 this.isbn = isbn;
 setTitle(title);
 }

 void setTitle(String title) {
 this.title = title;
 }

 @Override
 public boolean equals(Object obj) {
 if (obj instanceof Book) {
 return isbn == ((Book) obj).isbn;
 } else {
 return false;
 }
 }

 @Override
 public int hashCode() {
 return isbn;
 }

 @Override
 public String toString() {
 return title + "(ISBN: " + isbn + ")";
 }

}