public interface ILibraryBook {
    public void get(Reader rdr);
    public void ret();
}

public interface IReader {
    public void get(LibraryBook book);
    public void ret();
}
import java.util.GregorianCalendar;

public class Applicant {
    protected String name;
    protected double mark;
    protected GregorianCalendar date;
    public Applicant(GregorianCalendar date, String name, double mark)
    {
        this.date=date;
        this.name=name;
        this.mark=mark;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public double getMarks() {
        return mark;
    }
    public void setMarks(double marks) {
        this.mark = marks;
    }
    public GregorianCalendar getDate() {
        return date;
    }
    public void setDate(GregorianCalendar date) {
        this.date = date;
    }
    public String toString()
    {
        return "Name: "+this.name+", Date: "+date.toString()+", Mark: "+this.mark;
    }
}
import java.util.GregorianCalendar;

public class Student extends Applicant implements Comparable {

    protected String fn;

    public Student(GregorianCalendar date, String name, double mark, String fn) {
        super(date, name, mark);
        this.fn=fn;
    }
    public Student(String name, String fn) {
        super(new GregorianCalendar(), name, 0.);
        this.fn=fn;
    }

    public String getFn() {
        return fn;
    }

    public void setFn(String fn) {
        this.fn = fn;
    }

    public int compareTo(Object stud) {
        return this.fn.compareTo(((Student)stud).getFn());
    }
    public boolean equals(Object stud) {
        return this.fn.equals(((Student)stud).getFn());
    }
    public String toString()
    {
        return super.toString()+", FN: "+this.fn;
    }

}
import java.util.GregorianCalendar;

public class Reader extends Student implements IReader,Comparable{

    private LibraryBook readerBook;
    public Reader(String name, String fn)
    {
        super(name,fn);
    }
    public Reader(GregorianCalendar date, String name, double mark, String fn) {
        super(date, name, mark,fn);
    }

    public boolean equals(Object o)
    {
        return super.equals(o);
    }
    public int compareTo(Object o) {
        return super.compareTo(o);
    }
    public String toString()
    {
        return super.toString();
    }

    public void get(LibraryBook book) {
        this.readerBook=book;
    }

    public void ret() {
        this.readerBook=null;
    }

}

public class LibraryBook implements ILibraryBook,Comparable{
    private String name;
    private Reader reader;
    private boolean status;

    public LibraryBook(String name)
    {
        this.setName(name);
        this.setStatus(false);
    }
    public LibraryBook(String name, boolean status)
    {
        this.setName(name);
        this.setStatus(status);
    }
    public Reader getReader() {
        return reader;
    }
    public void setReader(Reader reader) {
        this.reader = reader;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public boolean isStatus() {
        return status;
    }
    public void setStatus(boolean status) {
        this.status = status;
    }
    public int compareTo(Object book)
    {
        return this.toString().compareTo(((LibraryBook)book).toString());
    }
    public String toString()
    {
        return "Name: "+this.name+",Status: "+((status)?"Occupied, Reader - "+this.reader.toString():"Unoccupied");

    }

    public void get(Reader rdr) {
        if(this.status) return;
        this.reader=rdr;
        this.status=true;
        rdr.get(this);
    }

    public void ret() {
        this.reader.ret();
        this.reader=null;
        this.status=false;
    }
}

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

    public static void readFile(String fName, ListLibraryBook lib)
    {
        lib.clear();
        try
        {
            Scanner sc=new Scanner(new File(fName));
            while(sc.hasNextLine())
            {
                lib.add(new LibraryBook(sc.next()));
            }
            sc.close();
        }
        catch(IOException e)
        {
            e.printStackTrace();
        }
    }
    public static void main(String[] args)
    {
        Library lib=new Library(DJava Secret Folder with UpdateUPR5srcbooks.txt,DJava Secret Folder with UpdateUPR5srcreaders.txt);
        lib.print();
        lib.borrowing(1, 3);
        lib.print();
        lib.sort();
        lib.print();
        System.out.println(lib.equalBooks(1,3));
        System.out.println(lib.equalReaders(0, 1));
    }
}