ArrayList implemented in custom list class Java

Question

I am trying to write a class that implements arraylist, but I will observe and repaint my gui whenever an element is added to the list, or removed from the list. Everything is syntactically right, but there seems to be a logic error in my code because I am getting a stackoverflowerror which leads me to believe that there is a recursive call somewhere that I am missing. The exact error is Exception in thread "main" java.lang.StackOverflowError at java.util.AbstractList.<init>(Unknown Source) at java.util.ArrayList.<init>(Unknown Source) at java.util.ArrayList.<init>(Unknown Source) at Library.<init>(Library.java:45) at LoanList.<init>(LoanList.java:14) at Library.<init>(Library.java:47) at LoanList.<init>(LoanList.java:14)

the actual code is around around 1k(1,000) lines so I will just post the bits that I think are to blame.

import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollBar;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Library implements Serializable, LibraryInterface, ActionListener{
    private static final long serialVersionUID = 1L;
    private List<Student> students;
    private List<Book> books;
    private LoanList<Loan> loans;
    private JButton ok, cancel;
    private JTextField utxt,ntxt,etxt;
    private JTextArea list;
    private JFrame frame;
    public Library(){
        students = new ArrayList<Student>();
        books = new ArrayList<Book>();
        loans = new LoanList<Loan>();
    }
    /* (non-Javadoc)
     * @see LibraryInterface#loadBooks()
     */
    /* (non-Javadoc)
     * @see LibraryInterface#loadBooks()
     */
    @Override
    public void loadBooks() throws ClassNotFoundException, IOException{
        FileInputStream fis = new FileInputStream("Books.txt");
        ObjectInputStream ois = new ObjectInputStream(fis);
        books = (ArrayList<Book>) ois.readObject();
        ois.close();
    }
    /* (non-Javadoc)
     * @see LibraryInterface#loadStudents()
     */
    /* (non-Javadoc)
     * @see LibraryInterface#loadStudents()
     */
    @Override
    public void loadStudents() throws ClassNotFoundException, IOException{
        FileInputStream fis = new FileInputStream("Students.txt");
        ObjectInputStream ois = new ObjectInputStream(fis);
        students = (ArrayList<Student>) ois.readObject();
        ois.close();
    }
    /* (non-Javadoc)
     * @see LibraryInterface#loadLoans()
     */
    /* (non-Javadoc)
     * @see LibraryInterface#loadLoans()
     */

    @Override
    public void loadLoans() throws ClassNotFoundException, IOException{
        FileInputStream fis = new FileInputStream("Loans.txt");
        ObjectInputStream ois = new ObjectInputStream(fis);
        loans = (LoanList<Loan>) ois.readObject();
        ois.close();
    }


import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;

public class LoanList<Loan> extends Library implements List<Loan>{
     /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private ArrayList<Loan> list;

     public LoanList(){
         list = new ArrayList<Loan>();
     }//Rest of the arraylist methods follow, however it's not constructing so no need to post

import java.io.Serializable;

public class Loan implements Serializable{
    private String uid;
    private String bookId;
    private String date;

    public Loan(String uid,String bookid,String date){
        this.uid = uid;
        this.bookId = bookid;
        this.date = date;
    }
    public String getUid() {
        return uid;
    }
    public String getBookId() {
        return bookId;
    }
    public String getDate() {
        return date;
    }
    public String toString(){
        String x="";
        x = "BookID: " + this.bookId + "\n" + "Student UID: " + this.uid + "\n" + "Date Checkedout: " + this.date + "\n" + "\n";
        return x;
    }

EDIT new repaint method

public void framePaint(){
    Collections.sort(students,new studentComparator());
    String result="";
    for(int i=0;i<students.size();i++){
        result += "\n" + students.get(i).toString() + "\n";
        for(int j=0;j<loans.size();j++){
            if(loans.get(j).getUid().equals(students.get(i).getUid())){
                result += "Book ID: " + loans.get(j).getBookId() + "\n";
            }
        }
    }
    list.setText(result);
    frame.repaint();

Comparator for reference

    public class studentComparator implements Comparator<Student>{
    @Override
    public int compare(Student arg0, Student arg1) {
        return arg0.getUid().compareTo(arg1.getUid());
    }
}

GUI for frame i am trying to repaint

    public void listStudents(){
    frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    JPanel panel = new JPanel();
    panel.setLayout(new BoxLayout(panel,1));
    list = new JTextArea("haha");
    list.setEditable(false);
    list.setBackground(Color.YELLOW);
    list.setForeground(Color.BLACK);
    Collections.sort(students,new studentComparator());
    String result="";
    for(int i=0;i<students.size();i++){
        result += "\n" + students.get(i).toString() + "\n";
        for(int j=0;j<loans.size();j++){
            if(loans.get(j).getUid().equals(students.get(i).getUid())){
                result += "Book ID: " + loans.get(j).getBookId() + "\n";
            }
        }
    }
    list.setText(result);
    panel.add(list);
    JScrollPane scroll = new JScrollPane(panel);
    frame.add(scroll);
    frame.setResizable(true);
    frame.setSize(300, 300);
    Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
    frame.setLocation(dim.width/2-frame.getSize().width/2, dim.height/2-frame.getSize().height/2);
    frame.setVisible(true);

Answer 1

LoanList is extending Library. Library's constructor makes a new LoanList. This new LoanList is a Library, so it creates a new LoanList. This new LoanList is a Library, so it creates a new LoanList. This new LoanList is a Library, so it creates a new LoanList. ad infinitum.