window not closing on dispose() call

Question

Below is my code.

It displays one table containing all daily sells, 3 buttons (next, previous, print). When we press next button date advances and next day sell will display in another window. Now here is the main problem - I want that when new window will open the first window should be closed. Can someone help me sort out this problem?

package shop;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.print.PrinterException;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.table.DefaultTableModel;
import shop.DBEngine;
public class AllCashTable extends JFrame implements ActionListener{
private static String name;
private Vector<Vector<String>> data; 
private Vector<Vector<String>> data1;
private Vector<String> header;
private Vector<String> header1;

JButton next,previous,print;
int a=0,d=0,y=0,m=0;
JTable table;
private JPanel mainPanel = new JPanel();
private String date,month,year;
String gt;
private String newdate;
private static JFrame frame,frame1,frame2;

public AllCashTable(String name) throws Exception{


    DBEngine dbengine = new DBEngine();
    data = dbengine.getDailySellAdd(name);
    header = new Vector<String>();
    header.add("Date"); 
    header.add("Cash"); 
    next=new JButton("Next");
    previous=new JButton("Previous");
    print=new JButton("Print");

    table = new JTable(data, header);
    table.setRowHeight(40);
    table.setSelectionBackground(Color.YELLOW);
    JPanel viewPanel = new JPanel();
    viewPanel.setLayout(new BorderLayout());
    viewPanel.add(table,BorderLayout.CENTER);
    JScrollPane scroll = new JScrollPane(viewPanel);
    scroll.setColumnHeaderView(table.getTableHeader());
    mainPanel.setLayout(new BorderLayout());
    mainPanel.setBorder(BorderFactory.createEtchedBorder());
    mainPanel.add(scroll,BorderLayout.CENTER);

    for(int i=0;i<table.getRowCount();i++){
        a=a+Integer.parseInt(data.get(i).get(1));
    }

    gt=Integer.toString(a);
    header1 = new Vector<String>();
    header1.add("Total");
    header1.add(gt);

    data.setSize(table.getRowCount()+1);
    data.set(table.getRowCount()-1, header1);


    JLabel jlab=new JLabel("Total:");
    String gt=Integer.toString(a);
    JLabel jlab3=new JLabel(gt);
    JLabel jlab4=new JLabel("       ");
    JPanel viewPanel2=new JPanel();
    viewPanel2.add(jlab);
    viewPanel2.add(jlab3);
    viewPanel2.add(jlab4);
    viewPanel2.add(previous);
    viewPanel2.add(next);
    viewPanel2.add(print);
    previous.addActionListener(this);
    print.addActionListener(this);
    next.addActionListener(this);
    mainPanel.add(viewPanel2,BorderLayout.PAGE_END);


}
public JPanel getMainPanel(){
    return mainPanel;
}
private static void createAndShowUI() throws Exception{
    frame = new JFrame("Cash Memo");
    frame.getContentPane().add(new AllCashTable(name).getMainPanel());
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(330,400);
    //frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
    //frame.setVisible(false);
}
public static void main(String[] args){
    java.awt.EventQueue.invokeLater(new Runnable(){
        public void run(){
            try {
                createAndShowUI();
            } catch (Exception ex) {
               Logger.getLogger(AllCashTable.class.getName()).log(Level.SEVERE,null,ex);
            }
        }
    });
}

@Override
public void actionPerformed(ActionEvent e) {
    if(e.getSource()==next){
        date=data.get(0).get(0);

        String m[]={"01","02","03","04","05","06","07","08","09","10","11","12"};
        Calendar cal=Calendar.getInstance();
        date=date.substring(0, 2);
        d=Integer.parseInt(date)+1;

        newdate=(d+"/"+m[cal.get(Calendar.MONTH)]+"/"+cal.get(Calendar.YEAR));


        frame1 = new JFrame("Cash Memo");
            try {

                frame1.getContentPane().add(new AllCashTable(newdate).getMainPanel());
            } catch (Exception ex) {
                Logger.getLogger(AllCashTable.class.getName()).log(Level.SEVERE, null, ex);
            }
        frame1.setSize(330,400);
        //frame.pack();
        frame1.setLocationRelativeTo(null);
        frame1.setVisible(true);
        frame.dispose();//here is error nullpointerexception

    }if(e.getSource()==previous){
        date=data.get(0).get(0);
        String m[]={"01","02","03","04","05","06","07","08","09","10","11","12"};
        Calendar cal=Calendar.getInstance();
        date=date.substring(0, 2);
        int ax=Integer.parseInt(date)-1;
        System.out.println(ax);
        newdate=(ax+"/"+m[cal.get(Calendar.MONTH)]+"/"+cal.get(Calendar.YEAR));

        frame2 = new JFrame("Cash Memo");
            try {

                frame2.getContentPane().add(new AllCashTable(newdate).getMainPanel());
            } catch (Exception ex) {
                Logger.getLogger(AllCashTable.class.getName()).log(Level.SEVERE, null, ex);
            }
        //frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame2.setSize(330,400);
        //frame.pack();
        frame2.setLocationRelativeTo(null);
        frame2.setVisible(true);
        //frame1.setVisible(false);
    }if(e.getSource()==print){
        try {
    boolean complete = table.print();
        if (complete) {
            /* show a success message  */
            System.out.println("Printing Complete");
        } else {
            /*show a message indicating that printing was cancelled */
            System.out.println("Not Printed");
        }
    } catch (PrinterException pe) {
        /* Printing failed, report to the user */
         System.out.println(pe);
    }
    }
   }
 }

Answer 1

For closing your JFrame use next code in your actionPerformed() method:

frame.setVisible(false);
frame.dispose();

EDIT: Your error in next you also create a new frame in a new variable use next code it help use, also watch @MadProgrammer suggetion about multiple frames.

    if (e.getSource() == next) {
        date = data.get(0).get(0);

        String m[] = { "01", "02", "03", "04", "05", "06", "07", "08",
                "09", "10", "11", "12" };
        Calendar cal = Calendar.getInstance();
        date = date.substring(0, 2);
        d=Integer.parseInt(date)+1;

        newdate = (d + "/" + m[cal.get(Calendar.MONTH)] + "/" + cal
                .get(Calendar.YEAR));

        frame.dispose();// here is error nullpointerexception
        frame.setVisible(false);
        frame = new JFrame("Cash Memo");
        try {

            frame.getContentPane().add(new Form(newdate).getMainPanel());
        } catch (Exception ex) {
            Logger.getLogger(Form.class.getName()).log(Level.SEVERE, null,
                    ex);
        }
        frame.setSize(330, 400);
        // frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);

    }

Answer 2

Do this:

frame.dispatchEvent(new WindowEvent(frame, WindowEvent.WINDOW_CLOSING));