Question

i am trying to retrieve data from a database and display then on a table in java. Below is the code sample, can someone tell me whats wrong wiz it because when an running it i am getting the following error:
java.lang.NullPointerException.

package sample;

import java.awt.Dimension;
import java.awt.FlowLayout;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import net.proteanit.sql.DbUtils;

public class Table extends JFrame{
    JTable table;
    Connection conn = null;
    ResultSet rs = null;
    PreparedStatement pst = null;

    private void UpdateJTable(){
    String sql = "select firstname, status from tblmember";

    try{
        pst = conn.prepareStatement(sql);
        rs = pst.executeQuery();
        table.setModel(DbUtils.resultSetToTableModel(rs));
    }
    catch(Exception e){
        JOptionPane.showMessageDialog(null, e);
    }
    }
    private void conect(){
        conn = myconnection.ConnectDb();        
}

    public Table(){
        setLayout(new FlowLayout());

        String [] columnName={"Name", "Status"};

        Object [][] data={
            {null, null},
            {null, null}
        };

        table = new JTable(data, columnName);
        table.setPreferredScrollableViewportSize(new Dimension(500,50));
        table.setFillsViewportHeight(true);

        JScrollPane sp = new JScrollPane(table);
        add(sp);
    }


    public static void main(String[] args){
        Table gui = new Table();
        gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        gui.setSize(700, 500);
        gui.setVisible(true);
        gui.setTitle("AAAAAAAA");
        gui.UpdateJTable();
        gui.conect();
    }
}

Answer 1

Try inverting the order of these two lines:

gui.UpdateJTable();
gui.conect();

to

gui.conect();
gui.UpdateJTable();

conn is null when you try and update.