java ch 9.6-7 problem

public interface Priority {

    public void setPriority();
    public int getPriority();
}
import java.io.*;
import java.util.*;
import java.util.GregorianCalendar;
public class ToDoList {
    int nextYear;
    int nextDay;
    int nextMonth;
    String Descrip;
    GregorianCalendar date;
    int Pri;
    int Year;
    int Month;
    int Day;

    ArrayList <ToDoList> taskList= new ArrayList<ToDoList>();
    Task k= new Task(Descrip, date, Pri);
    public void go(){
        try
          {retrieveTasks();}

        catch(IOException e)
            {e.printStackTrace();}
        }

    void retrieveTasks() throws IOException{
        Scanner fileScanner= new Scanner(new File("Data/tasks.txt"));
        while(fileScanner.hasNext()){
            String Descrip= fileScanner.next();
            //System.out.println(Descrip);
            int nextYear= fileScanner.nextInt();
            //System.out.println(nextYear);
            int nextMonth= fileScanner.nextInt();
            //System.out.println(nextMonth);
            int nextDay= fileScanner.nextInt();
            //System.out.println(nextDay);
            int Pri= fileScanner.nextInt();
            //System.out.println(Pri);
            nextYear=Year;
            nextMonth= Month;
            nextDay= Day;
            GregorianCalendar d= new GregorianCalendar(Year, Month, Day);
            System.out.println(d);
        }}
}
import java.io.*;
import java.util.*;
import java.util.GregorianCalendar;

public class TaskManager {
    int nextYear;
    int nextMonth;
    int nextDay;
    GregorianCalendar date;

    ArrayList <ToDoList> taskList= new ArrayList<ToDoList>();
    public static void main(String[] args){
    ToDoList t= new ToDoList();
    t.go();
    }
}

public class taskCompare{
     public int compare(Task t1, Task t2){
        return t1.getTask().compareTo(t2.getTask());
    }
}
import java.util.GregorianCalendar;
import java.io.*;
import java.util.*;

public class Task implements Comparable, Priority{
    public String Descrip;
    public GregorianCalendar dueDate;
    public int Pri;
    public int p;
    public Task t;
    public String s;
    public GregorianCalendar calDate;
    public GregorianCalendar date;

    ArrayList <ToDoList> taskList= new ArrayList<ToDoList>();

    public Task(String Descrip, GregorianCalendar date, int Pri){
        this.Descrip= Descrip;
        this.date= calDate;
        this.Pri= Pri;
    }

    public void setDueDate(GregorianCalendar date){
        date= calDate;
    }

    public int compareTo(Task t){
        return calDate.compareTo(t.getDueDate());
    }

    public GregorianCalendar getDate(){
        return calDate;
    }

    private GregorianCalendar getDueDate() {
        return calDate;
    }

    public void setTask(){
        this.Descrip=Descrip;
    }

    public String getTask(){
        return s;
    }

    public void setPriority() {
        Pri= Pri;
    }

    public int getPriority() {
        return Pri;
    }

    public String toString() {
        return Descrip + " is due " + dateString()+" with a priority of "+Pri;
    }

    public String dateString() {
        return calDate.getTime().toString(); }
}
public class GregorianCalendar extends ToDoList {
    String nextYear;
    String nextMonth;
    String nextDay;
    int Year;
    int Month;
    int Day;
    GregorianCalendar date;
    public GregorianCalendar(int Year, int Month, int Day){
        this.Year= Year;
        this.Month=Month;
        this.Day= Day;
        GregorianCalendar date= new GregorianCalendar(Year, Month, Day);
        //System.out.println(Year+" "+Month+" "+Day);
    }

}

data in text file to read with Scanner:
take-out-trash 2013 3 19 8
program-in-Java 2013 3 16 2
study-for-java-final 2013 4 27 1