hi i have been working on my project to create a store and i have to add items and sell items, and once i add items i store them into a textfile separated by commas, and i made the add item button work perfectly but i am having trouble with the sell button.

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;
import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;

public class text_feild implements ActionListener {

    JPanel titlePanel, buttonPanel;
    JButton button, Sell_button;
    InputStreamReader input_stream = new InputStreamReader(System.in);
    BufferedReader read_Buffer;
    FileOutputStream file_out_put;
    PrintStream print_stream;
    FileReader read_from_file;

    JTextField field_id = new JTextField(20);
    JTextField field_name = new JTextField(20);
    JTextField field_price = new JTextField(20);
    JTextField field_sq = new JTextField(20);

    public JButton Add_Product() {

        JFrame frame = new JFrame("Adding Items");
        JPanel panel = new JPanel();
        button = new JButton("Save Items");

        JLabel lab_id = new JLabel("ID #:");
        JLabel lab_name = new JLabel("Name:");
        JLabel lab_price = new JLabel("Price:");
        JLabel lab_sq = new JLabel("Quantity: ");

        button.addActionListener(this);

        lab_id.setLocation(0, 0);
        lab_id.setSize(50, 50);
        frame.add(lab_id);
        field_id.setLocation(100, 15);
        field_id.setSize(80, 20);
        frame.add(field_id);

        lab_name.setLocation(0, 25);
        lab_name.setSize(50, 50);
        frame.add(lab_name);
        field_name.setLocation(100, 40);
        field_name.setSize(130, 20);
        frame.add(field_name);

        lab_price.setLocation(0, 50);
        lab_price.setSize(50, 50);
        frame.add(lab_price);
        field_price.setLocation(100, 65);
        field_price.setSize(130, 20);
        frame.add(field_price);

        lab_sq.setLocation(0, 70);
        lab_sq.setSize(75, 50);
        frame.add(lab_sq);
        field_sq.setLocation(100, 90);
        field_sq.setSize(130, 20);
        frame.add(field_sq);

        frame.getContentPane().add(BorderLayout.CENTER, panel);
        frame.getContentPane().add(BorderLayout.SOUTH, button);
        frame.setSize(350, 300);
        frame.setVisible(true);
        return button;
    }

    public JButton Sell_Product() {

        JFrame frame = new JFrame("Sell Items");
        JPanel panel = new JPanel();
        Sell_button = new JButton("Buy Items");

        JLabel lab_id = new JLabel("ID #:");
        JLabel lab_name = new JLabel("Name:");
        JLabel lab_price = new JLabel("Price:");
        JLabel lab_sq = new JLabel("Quantity: ");

        Sell_button.addActionListener(this);

        lab_id.setLocation(0, 0);
        lab_id.setSize(50, 50);
        frame.add(lab_id);
        field_id.setLocation(100, 15);
        field_id.setSize(80, 20);
        frame.add(field_id);

        lab_name.setLocation(0, 25);
        lab_name.setSize(50, 50);
        frame.add(lab_name);
        field_name.setLocation(100, 40);
        field_name.setSize(130, 20);
        frame.add(field_name);

        lab_price.setLocation(0, 50);
        lab_price.setSize(50, 50);
        frame.add(lab_price);
        field_price.setLocation(100, 65);
        field_price.setSize(130, 20);
        frame.add(field_price);

        lab_sq.setLocation(0, 70);
        lab_sq.setSize(75, 50);
        frame.add(lab_sq);
        field_sq.setLocation(100, 90);
        field_sq.setSize(130, 20);
        frame.add(field_sq);

        frame.getContentPane().add(BorderLayout.CENTER, panel);
        frame.getContentPane().add(BorderLayout.SOUTH, Sell_button);
        frame.setSize(350, 300);
        frame.setVisible(true);
        return Sell_button;
    }

    public void actionPerformed(ActionEvent b) {
        Transcation tn = new Transcation (); 
        JFrame f = new JFrame();
        String id = field_id.getText().trim();
        String name = field_name.getText().trim();
        String price = field_price.getText().trim();
        String quantity = field_sq.getText().trim();
        Integer[] value=new Integer[5];

        if (b.getSource() == button) {

            if (id == null || id.equals("") || name == null || name.equals("")
                    || price == null || price.equals("") || quantity == null
                    || quantity.equals("")) 
            {
                JOptionPane.showMessageDialog(f, "Information was left out");
            } 
            else {
                try {
                    file_out_put = new FileOutputStream("Item.txt", true);
                    print_stream = new PrintStream(file_out_put);
                    print_stream.println(id + "," + name + "," + price + ","
                            + quantity);
                    file_out_put.close();
                } catch (Exception ex) {
                    System.out.println("There was a problem with the system");
                }
            }
        }

        else if (b.getSource() == Sell_button) {
            try
            {

                int ID = Integer.parseInt(id);
                int PRICE = Integer.parseInt(price);
                int QUY = Integer.parseInt(quantity);

                tn.makeTransaction();

                    file_out_put=new FileOutputStream("Transaction.txt",true);
                    print_stream=new PrintStream(file_out_put);
                    print_stream.println(ID+","+name+","+PRICE+","+QUY);
                    file_out_put.close();                   

                System.out.println("Transaction has been successful");  
            }
            catch(Exception ex)
            {
                System.out.println("There was a problem with the SELL");
            }

            JOptionPane.showMessageDialog(f, "Congrats on your item");
        }
    }
    private String findProduct(String pID) throws IOException
    {
        int counter=0,i=0,flag=0;
        String s;
        String cline[]=new String[255];
        String cID[]=new String[5];
        String value=" ";

        read_from_file=new FileReader("Item.txt");
        read_Buffer=new BufferedReader(read_from_file);

        try
        {
            while((s=read_Buffer.readLine()) != null)
            {
                counter=counter+1;
                cline[counter]=s;
                cID=cline[counter].split(",");
                if(cID[0].equals(pID))
                {
                    for(;i<cID.length;i++)
                    {
                        value=value+","+cID[i]; 
                    }
                    flag=1;
                    break;
                }
            }
            switch(flag)
            {
                case 0:
                    value="Product was not in system";
                    break;
                case 1:
                    value=value.substring(2);
                    break;                      
            }
        }
        catch(Exception ex)
        {
            System.out.println("There was a problem with the system");
        }

        return value;
    }

    //function for updating the value of current current_stock whenever a specific item is sold out
    private int updatecurrent_stock(int iD,int qUY) throws IOException
    {
        int counter=0,i=0,pos=0;
        String s;
        String cline[]=new String[255];
        String cID[]=new String[5];
        String row[]=new String[5];
        String item_descripton,price;
        int current_stock=0,status=0;

        try
        {
            read_from_file=new FileReader("Item.txt");
            read_Buffer=new BufferedReader(read_from_file);     

            while((s=read_Buffer.readLine()) != null)
            {
                counter=counter+1;
                cline[counter]=s;           
                cID=s.split(",");
                if(cID[0].equals(iD))
                {
                    pos=counter;
                    row=s.split(",");
                }   
            }

            file_out_put=new FileOutputStream("Item.txt",false);
            print_stream=new PrintStream(file_out_put);

            for(i=0;i<cline.length;i++)
            {           
                if(i==pos)
                {
                    item_descripton=row[1];
                    price=row[2];
                    current_stock=Integer.parseInt(row[3])-qUY;
                    print_stream.println(iD+","+item_descripton+","+price+","+current_stock);
                }
                else
                {
                    if(cline[i]!=null)
                    {
                        print_stream.println(cline[i]);
                    }
                }
            }
            file_out_put.close();   
            status=0;
        }
        catch(Exception ex)
        {
            status=1;   
        }
        return status;  
    }
}
private static void createAndShowGUI() {

            JFrame.setDefaultLookAndFeelDecorated(true);
            JFrame frame = new JFrame("Store");

            //Create and set up the content pane.
            ButtonDemo_Extended demo = new ButtonDemo_Extended();
            frame.setContentPane(demo.createContentPane());

            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setSize(500, 500);
            frame.setVisible(true);


        }

    public static void main(String args[]) throws IOException {
            createAndShowGUI();

    }

this is my code so far, i have many classes and this class is the class that deals with the add and sell function if any one could plese help it would be greatly appreatied thanks

Kindly paste the error or explain it. Reading a huge code is a bit difficult for every programmer.

well the problem is that i am unable to remove or minus the conent from my textfile when i sell a product

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