package mediasystem.media;import java.util.Date;public class MyBook extends MyMedia {  private Date publishDate;  private String bookISBN;  public String getPublishDate(){    String year = publishDate.getYear()%100 + "";    System.out.println( publishDate.getYear());    String month = publishDate.getMonth() + "";    String day = publishDate.getDay() + "";    return year+month+day;  }  public void setPublishDate(Date publishDate){    this.publishDate = publishDate;  }  public String getBookISBN(){    return bookISBN;  }  public void setBookISBN(String bookISBN){    this.bookISBN = bookISBN;  }}