从arraylist打印信息

Question

public class Program6 
{
    private static String FMT1 = "%-15s %-15s %-5s %-5s %n";

    public static void main(String[] args)
    {
        String edit;

        StudType type = new StudType();
        ArrayList<StudType> list = new ArrayList<StudType>();

        Scanner sc = new Scanner(System.in);

        type.printHeader();

        while (sc.hasNext())
        {
            edit = sc.next();

            if (edit.equals("A"))
            {
                type.getDataFromFile(sc);
                if (type.InvalidStudType())
                {
                    type.printInvalid();
                }
                else
                    list.add(type);
            }

            if (edit.equals("D"))
            {
                if (list.isEmpty())
                {
                    System.out.println("~~>List is empty! No Deleting!");
                }
                else
                {
                    int delete = sc.nextInt();
                    for (int i = 0; i < list.size(); i++)
                    {
                        if (delete == list.get(i).studId)
                        {
                            list.remove(i);
                            break;
                        }
                    }
                }
            }

            if (edit.equals("P"))
            {
                if (list.isEmpty())
                {
                    System.out.println("~~>List is empty! No Printing!");
                }
                else
                    System.out.println(list);
            }

            if (edit.equals("C"))
            {
                if (list.isEmpty())
                {
                    System.out.println("~~>List is empty! No Clearing!");
                }
                else
                    list.clear();
            }
        }
        type.printFooter();
    }
}

无法弄清楚为什么得到[StudType@677327b6, StudType@677327b6]而不是输出444 Zoom，Joe 3.33 M。

如果我使用printf(format, studentId, name, gpa, sex)，它只打印列表中的最后一个元素而不是整个列表。不知道该怎么做。

import java.io.*;
import java.util.*;

public class StudType
{
    public static int studId;
    public static double gpa;
    public static String name, sex;
    private static String FMT1 = "%-15s %-15s %-5s %-5s %n";
    private static String FMT2 = "%-15s %-10s %-15s %-5s %-5 %n";

    public static void printHeader()
    {
        System.out.println("<~~~~~~~~~~~~~~~~~ GPA Report ~~~~~~~~~~~~~~~~~~~~~>");
        System.out.println("");
        System.out.printf(FMT1, "STUDENT ID", "N A M E", "GPA", "SEX");
        System.out.printf(FMT1, "----------", "-------", "---", "---");
    }

    public void getDataFromFile(Scanner sc)
    {
        studId = sc.nextInt();
        name = sc.next();
        gpa = sc.nextDouble();
        sex = sc.next();
    }

    public boolean InvalidStudType()
    {
        if (studId < 111 && studId > 999) {
            if (gpa < 0.0 && gpa > 4.00) {
                if (!sex.equals("M") && !sex.equals("F")) {
                    return true;
                }
            }
        }
        return false;
    }
    public static void printInvalid()
    {
        System.out.printf(FMT2, studId, name, gpa, sex, "**** Invalid Data");

    }

    public static void printFooter()
    {
        System.out.println(">>>* End Of GPA Report *<<<");
    }

}