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How do i write to a database by taking user input from a GUI and storing that user input into a database in java?

I've recently been trying to write to a Database by taking user input from a GUI and I would like to store that user input from the GUI in a derby database on netbeans. At the moment, I have got some code but it does not seem to be functional as when i run the GUI and start inputting the data that is supposed to be stored in the back end of my program in the database, it does not store that data which is being inputted in the GUI. It does not load any data onto the database!
Here is the code for writing to the Database:
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/**
*
* #author Hammad
*/
public class WritePlayerDB
{
private final DBConnection dbc;
private final Connection conn;
private Statement stmt;
String insertQuery;
public WritePlayerDB()
{
dbc = new DBConnection();
conn = dbc.getConnection();
}
public void writeToPlayerDB()
{
try {
int playerID = 0;
insertQuery = "INSERT INTO 'PLAYERINFO' ('PLAYER_ID', 'PLAYER_NAME', 'PRIZE_WON', 'CORRECT_ANSWERS')" + "VALUES(1,2,3,4)";
this.stmt = conn.createStatement();
this.checkExistedTable("PLAYERS");
PreparedStatement ps = conn.prepareStatement(insertQuery);
CorrectAnswers.correctAnswers[MillionaireGui.moneyCounter] = PrizeMoney.prizeLadder[MillionaireGui.moneyCounter];
ps.setInt(1, playerID++);
ps.setString(2, MillionaireGui.nameField.getText());
ps.setInt(3, PrizeMoney.prizeLadder[MillionaireGui.moneyCounter]);
ps.setInt(4, CorrectAnswers.correctAnswers[MillionaireGui.moneyCounter]);
ps.executeUpdate();
ps.close();
}
catch (SQLException ex)
{
System.out.println(ex.getMessage());
}
}
public void checkExistedTable(String name)
{
try {
DatabaseMetaData dbmd = this.conn.getMetaData();
String[] types = {"TABLE"};
stmt = this.conn.createStatement();
ResultSet rs = dbmd.getTables(null, null, null, types);
while (rs.next()) {
String table_name = rs.getString("TABLE_NAME");
System.out.println(table_name);
if (table_name.equalsIgnoreCase(name)) {
stmt.executeUpdate("Drop table " + name);
System.out.println("Table " + name + " has been deleted.");
break;
}
}
rs.close();
} catch (SQLException ex) {
System.out.println(ex.getMessage());
}
}
}
and I am calling the writeToPlayerDB() method in the actionListener for my GUI's JTextField as shown below:
nameField.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
if (nameField.getText().equals(""))
{
blankName.setVisible(true);
blankName.setText("PLEASE DON'T LEAVE NAME BLANK");
}
else
{
playerName.setPlayerName(nameField.getText().toUpperCase());
WritePlayerDB wdb = new WritePlayerDB();
wdb.writeToPlayerDB();
blankNamePanel.setVisible(false);
introRuleScreen();
}
}
});
Would appreciate if i could get a hand with this as I have been stuck on it for a long time!

There's not enough information to go by to truely understand what your core problem is, how ever...
static is not a good idea, especially when you're dealing with UI elements, as you might have more then one instance of the UI and then you can no longer determine which instance of the element you're actually referencing. Better to make use of dependency injection and pass the information to the method directly.
+ "VALUES(1,2,3,4)" s not how you use PreparedStatement, see Using Prepared Statements for more details
Also...
int playerID = 0;
//...
ps.setInt(1, playerID++);
means that the player id is ALWAYS 0 (the ++ is a postfix operation; assignment first, addition second). In fact, you should avoid at all costs, manually creating record ids like this and the database should be making use of "auto incrementing" values internally. See Autogenerated keys for more details.
For simplicty, I use the H2 Database Engine for the following example. It should otherwise work with Derby, but you'll want to remove the createTables method
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.StringJoiner;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JSpinner;
import javax.swing.JTextField;
import javax.swing.SpinnerNumberModel;
import javax.swing.border.EmptyBorder;
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
DatabaseManager db = new DatabaseManager();
db.open();
JFrame frame = new JFrame();
frame.add(new MainPane(db));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (SQLException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
public class MainPane extends JPanel {
private JTextField nameField;
private JSpinner moneyCounter;
public MainPane(DatabaseManager database) {
setBorder(new EmptyBorder(32, 32, 32, 32));
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.anchor = GridBagConstraints.LINE_END;
gbc.insets = new Insets(4, 4, 4, 4);
add(new JLabel("Name: "), gbc);
gbc.gridy++;
add(new JLabel("Counter: "), gbc);
gbc.gridx = 1;
gbc.gridy = 0;
gbc.anchor = GridBagConstraints.LINE_START;
nameField = new JTextField(10);
moneyCounter = new JSpinner(new SpinnerNumberModel(0, 0, 100, 10));
add(nameField, gbc);
gbc.gridy++;
add(moneyCounter, gbc);
JButton btnSave = new JButton("Save");
btnSave.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String name = nameField.getText();
if (name.isBlank()) {
JOptionPane.showMessageDialog(MainPane.this, "Name can not be blank", "Error", JOptionPane.ERROR_MESSAGE);
return;
}
try {
int playerId = database.savePlayer(name, (int) moneyCounter.getValue());
List<String> results = database.getPlayerById(playerId);
StringJoiner sj = new StringJoiner("<br>", "<html>", "</html>");
for (String text : results) {
sj.add(text);
}
JOptionPane.showMessageDialog(MainPane.this, sj.toString(), "Success", JOptionPane.PLAIN_MESSAGE);
} catch (SQLException ex) {
ex.printStackTrace();
JOptionPane.showMessageDialog(MainPane.this, "Failed to create player record", "Error", JOptionPane.ERROR_MESSAGE);
}
}
});
gbc.gridy++;
gbc.gridx = 0;
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.anchor = GridBagConstraints.CENTER;
add(btnSave, gbc);
}
}
public class DatabaseManager {
private Connection connection;
protected void createTables() throws SQLException {
String cmd = "create table IF NOT EXISTS PLAYERINFO ("
+ "PLAYER_ID bigint GENERATED BY DEFAULT AS IDENTITY(START WITH 0) PRIMARY KEY,"
+ "PLAYER_NAME varchar(255) not null,"
+ "PRIZE_WON int not null,"
+ "CORRECT_ANSWERS int not null"
+ ")";
try (Statement stmt = connection.createStatement()) {
stmt.execute(cmd);
}
}
public void open() throws SQLException {
if (connection != null && !connection.isClosed()) {
try {
connection.close();
} catch (SQLException ex) {
Logger.getLogger(Main.class.getName()).log(Level.WARNING, null, ex);
}
}
connection = DriverManager.getConnection("jdbc:h2:~/test");
createTables();
}
public void close() throws SQLException {
if (connection == null) {
return;
}
try {
if (connection.isClosed()) {
connection = null;
}
connection.close();
} finally {
connection = null;
}
}
public int savePlayer(String name, int counter) throws SQLException {
String cmd = "insert into PLAYERINFO (PLAYER_NAME, PRIZE_WON, CORRECT_ANSWERS) values (?, ?, ?)";
try (PreparedStatement stmt = connection.prepareStatement(cmd, Statement.RETURN_GENERATED_KEYS)) {
Random rnd = new Random();
stmt.setString(1, name);
stmt.setInt(2, rnd.nextInt(100) + 1);
stmt.setInt(3, counter);
if (stmt.executeUpdate() != 1) {
throw new SQLException("Unexpectedly modified more then one row");
}
try (ResultSet rs = stmt.getGeneratedKeys()) {
if (rs.next()) {
return rs.getInt(1);
}
}
}
throw new SQLException("Failed to create player record");
}
public List<String> getPlayerById(int id) throws SQLException {
String cmd = "select * from playerinfo where PLAYER_ID = ?";
List<String> results = new ArrayList<>(8);
try (PreparedStatement stmt = connection.prepareStatement(cmd)) {
stmt.setInt(1, id);
try (ResultSet rs = stmt.executeQuery()) {
while (rs.next()) {
String name = rs.getString("PLAYER_NAME");
int prizeWon = rs.getInt("PRIZE_WON");
int correctAnswer = rs.getInt("CORRECT_ANSWERS");
results.add(name + " won " + prizeWon + " with " + correctAnswer + " correct answers");
}
}
}
return results;
}
}
}

Retrieving a image in BLOB format from one table and storing it in another table

Here i am trying to retrieve a image stored in BLOB format and storing it in another table in the same BLOB format only! And one more issue is this that i have a JFrame named WelcomeStaffs from which i have to access the JTextField named subject_txt and staff_txt values and store it in the database.. But those are only blank! Not getting printed in the output, while i print it!
Here is the code of the FaceRecognizer class..
import static cern.jet.math.Bessel.i1;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import facedetection.*;
import com.googlecode.javacv.*;
import com.googlecode.javacv.cpp.*;
import com.googlecode.javacpp.Loader;
import com.mysql.jdbc.Connection;
import java.sql.Blob;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
public class FaceRecognizer extends JFrame
{
// GUI components
private FaceRecogPanel facePanel;
private JButton recogBut;
private JTextField nameField; // where the name (and distance info) appears
private JButton done;
private JButton exit;
public FaceRecognizer()
{
super("Face Recognizer");
FaceRecognizer fac;
Container c = getContentPane();
c.setLayout( new BorderLayout() );
// Preload the opencv_objdetect module to work around a known bug.
Loader.load(opencv_objdetect.class);
facePanel = new FaceRecogPanel(this); // the sequence of pictures appear here
c.add( facePanel, BorderLayout.CENTER);
// button for recognizing a highlighted face
done = new JButton("Done");
recogBut = new JButton("Recognize Face");
recogBut.addActionListener( new ActionListener() {
public void actionPerformed(ActionEvent e)
{ nameField.setText("");
recogBut.setEnabled(false);
facePanel.setRecog();
}
});
done.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
WelcomeStaffs wc = new WelcomeStaffs();
Connection con = null;
try{
String url = "jdbc:mysql://localhost:3306/facedetection";
Class.forName("com.mysql.jdbc.Driver");
System.out.println("Conncection Success");
con = (Connection) DriverManager.getConnection(url, "root", "2204");
System.out.println("Database Connected");
}
catch(Exception ex)
{
System.out.println("Exception = "+ex);
}
String nm = nameField.getText().toUpperCase();
String name ="",course="";
System.out.println("Hello im till here!!");
String subject = wc.subject_txt.getText();
String staff = wc.staff_txt.getText();
String day = wc.day_txt.getText();
String date = wc.date_txt.getText();
String time = wc.time_txt.getText();
int roll_no = 0;
System.out.println(subject+staff);
String sql = "SELECT roll_no,name,course,photo FROM students WHERE name=?";
try {
PreparedStatement ps = con.prepareStatement(sql);
ps.setString(1,nm);
ResultSet rs = ps.executeQuery();
while(rs.next()) //retrieving values from database and storing it!
{
roll_no = rs.getInt("roll_no");
name = rs.getString("name");
course = rs.getString("course");
byte[]imagedata = rs.getBytes("photo");
image = Toolkit.getDefaultToolkit().createImage(imagedata);
format = new ImageIcon(image);
System.out.println("Retrieved Data!!!!!!!");
}
} catch (SQLException ex) {
Logger.getLogger(FaceRecognizer.class.getName()).log(Level.SEVERE, null, ex);
}
try{
if(roll_no == 0 || name.equals("") || course.equals(""))
{
System.out.println("EMPTY");
}
else
{
sql = "INSERT INTO attendance(roll_no, name, course, subject, staff, day, time, date, photo) VALUES(?,?,?,?,?,?,?,?,?)";
PreparedStatement ps1 = con.prepareStatement(sql);
ps1.setInt(1,roll_no);
ps1.setString(2,name);
ps1.setString(3,course);
ps1.setString(4,subject);
ps1.setString(5,staff);
ps1.setString(6,day);
ps1.setString(7,time);
ps1.setString(8,date);
ps1.setBlob(9, (Blob) format);
int i1 = ps1.executeUpdate();
JOptionPane.showMessageDialog(null,i1+" Data Inserted");
}
}
catch(Exception ec)
{
System.out.println(""+ec);
}
}
});
nameField = new JTextField(20); // for the name of the recognized face
nameField.setEditable(false);
JPanel p = new JPanel();
p.add(recogBut);
p.add( new JLabel("Name: "));
p.add( nameField);
p.add(done);
c.add(p, BorderLayout.SOUTH);
addWindowListener( new WindowAdapter() {
public void windowClosing(WindowEvent e)
{ facePanel.closeDown(); // stop snapping pics
/*Attendance_Chart ac = new Attendance_Chart();
ac.setVisible(true);*/
System.exit(0);
}
});
pack();
setResizable(false);
setVisible(true);
} // end of FaceRecognizer()
public void setRecogName(final String faceName, final String dist)
// update face name and its distance in the nameField; called from panel
{
SwingUtilities.invokeLater(new Runnable() {
public void run()
{ nameField.setText( faceName);
recogBut.setEnabled(true);
}
});
} // end of setRecogName()
// -------------------------------------------------------
public static void main( String args[] )
{
new FaceRecognizer();
}
public ImageIcon format = null;
public Image image = null;
public Blob blob = null;
}
// end of FaceRecognizer class
Here is the output i get!
Conncection Success for Staffs
detection/recognition duration: 9ms
Database Connected for Staffs
Table Created
Conncection Success
Database Connected
Hello im till here!!
Retrieved Data!!!!!!!
java.lang.ClassCastException: javax.swing.ImageIcon cannot be cast to `java.sql.Blob`
Please help!
Thank you!

How do i get the id of the cell click using JTable?

I am using a JTable to display data from my database. What I want to happen is that when a row is clicked it opens another window.
My Code
Connection to the database
public class JFrametest extends javax.swing.JFrame {
private static Connection connection;
private static Statement stmt;
static {
// standard code to open a connection and statement to Java Derby database
try {
NetworkServerControl server = new NetworkServerControl();
server.start(null);
// Load JDBC driver
Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
//Establish a connection
String sourceURL = "jdbc:derby://localhost:1527/"
+ new File("EmailsDB").getAbsolutePath() + ";";
connection = DriverManager.getConnection(sourceURL, "student", "student");
stmt = connection.createStatement();
} // The following exceptions must be caught
catch (ClassNotFoundException cnfe) {
out.println(cnfe);
} catch (SQLException sqle) {
out.println(sqle);
} catch (Exception e) {
System.out.println(e);
}
}
Displaying Data from the database
try {
String query = "select * from messages";
PreparedStatement pst = connection.prepareStatement(query);
ResultSet rs = pst.executeQuery();
table.setModel(DbUtils.resultSetToTableModel(rs));
}catch (Exception e) {
e.printStackTrace();
}
As anyone got any ideas on what i can do? is this possible?

You could use a mouseClicked Action Listener to do this.

You can use MouseListener for that, here is simple example:
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
public class TestFrame extends JFrame {
public static void main(String... s) {
new TestFrame();
}
private JTable t;
public TestFrame() {
init();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setLocationRelativeTo(null);
setVisible(true);
}
private void init() {
DefaultTableModel model = new DefaultTableModel(0,2);
for(int i=0;i<10;i++){
model.addRow(new Object[]{i,"other info "+i});
}
model.setColumnIdentifiers(new Object[]{"id","info"});
t = new JTable(model);
t.addMouseListener(getListener());
add(new JScrollPane(t));
}
protected void showDialog(int rowAtPoint) {
Object valueAt = t.getValueAt(rowAtPoint, 0);
// other operations
JDialog d = new JDialog();
d.setTitle("id="+valueAt);
d.setModal(true);
d.setAlwaysOnTop(true);
d.setLocationRelativeTo(null);
d.pack();
d.setVisible(true);
}
private MouseListener getListener() {
return new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
super.mouseClicked(e);
if(e.getClickCount() >= 1){
int rowAtPoint = t.rowAtPoint(e.getPoint());
if(rowAtPoint != -1)
showDialog(rowAtPoint);
}
}
};
}
}

Deleting record from sqlite database using Java

I can't seem to figure out how to delete a record from a sqlite database created via java. I was trying to identify the record with the primary id but I just keep getting a null pointer exception. Heres my code:
package userinterface;
import javax.swing.JFrame;
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import backend.SQLiteDb;
import business.Person;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.BorderLayout;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class GUI {
static SQLiteDb db;
public static void main(String[] args) {
final JFrame jframe = new JFrame();
JButton btnEnterInfo = new JButton("Enter Info");
jframe.getContentPane().add(btnEnterInfo, BorderLayout.CENTER);
jframe.setVisible(true);
jframe.setSize(300, 300);
btnEnterInfo.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JLabel fullName = new JLabel("Full Name: ");
JTextField nameField = new JTextField();
JLabel age = new JLabel("Age: ");
JTextField ageField = new JTextField();
JLabel address = new JLabel("Address: ");
JTextField addressField = new JTextField();
JLabel salary = new JLabel("Salary: ");
JTextField salaryField = new JTextField();
Object[] ob = { fullName, nameField, age, ageField, address,
addressField,
salary, salaryField };
int result = JOptionPane.showConfirmDialog(null, ob, "Part 5",
JOptionPane.OK_CANCEL_OPTION);
jframe.getContentPane().setLayout(new FlowLayout());
if (result == JOptionPane.OK_OPTION) {
db = new SQLiteDb();
db.createPersonnelTable();
String fullName1 = nameField.getText();
String userAge = ageField.getText();
String userAddress = addressField.getText();
String userSalary = salaryField.getText();
Person person = new Person(fullName1, Integer
.parseInt(userAge), userAddress,
Double.parseDouble(salaryField.getText()));
db.addPerson(person);
String sql = "SELECT * FROM COMPANY";
Statement stmt = null;
try {
java.sql.Statement s;
Connection connection = DriverManager
.getConnection("JDBC:sqlite:Andy.db");
stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery(sql);
while (rs.next()) {
int id_col = rs.getInt("ID");
String name = rs.getString("name");
int age1 = rs.getInt("Age");
String address1 = rs.getString("Address");
double salary1 = rs.getInt("Salary");
String output = id_col + " " + name + " " + age1
+ " " + address1 + " " + salary1;
System.out.println(output);
}
delete(3);
rs.close();
} catch (SQLException ee) {
System.out.println("ee error");
ee.printStackTrace();
} finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e1) {
// TODO Auto-generated catch block
System.out.println("e1 error");
e1.printStackTrace();
}
}
}
}
}
});
}
public static void viewTable(Connection con, String dbName)
throws SQLException {
}
public static void delete(int id) {
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
// connection = DriverManager.getConnection();
preparedStatement = connection.prepareStatement("DELETE FROM person WHERE id = ?");
preparedStatement.setInt(1, id);
preparedStatement.executeUpdate();
System.out.println("DELETE FROM person WHERE id = ?");
} catch (Exception eeee) {
eeee.printStackTrace();
} finally {
if (preparedStatement != null) {
try {
preparedStatement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}}}

connection is null in your delete method, why wouldn't you get NullPointerException?
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
// connection = DriverManager.getConnection(); <--- !!!! This line is commented for some reason, so it is not executed!
preparedStatement = connection.prepareStatement("DELETE FROM person WHERE id = ?");
preparedStatement.setInt(1, id);
preparedStatement.executeUpdate();
The rest of your code in your delete method looks ok, you just need to initialize your connection variable to something.
A possible solution is to store this variable in a method field instead of a local variable when you are initializing it in your actionPerformed method:
this.connection = DriverManager
.getConnection("JDBC:sqlite:Andy.db");
Then you could use:
preparedStatement = this.connection.prepareStatement("DELETE FROM person WHERE id = ?");
which would re-use the previously initialized connection. (Re-using connection object is a good idea)

My Java Swing Log in Form won't work

I finally got the password, the queries, the button and the connection, but how come it Seems I can't seem to log in? what's wrong with my Action Handler? please check my code
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JPasswordField;
import javax.swing.JButton;
import javax.swing.JPanel;
import java.sql.*;
public class Login extends JFrame {
private JLabel label1, label2;
private JButton submit;
private JTextField textfield1;
private JPasswordField passfield;
private JPanel panel;
public Login() {
setSize(300, 100);
setVisible(true);
label1 = new JLabel("User ID:");
textfield1 = new JTextField(15);
label2 = new JLabel("Password:");
passfield = new JPasswordField(15);
submit = new JButton("Submit");
panel = new JPanel(new GridLayout(3, 1));
panel.add(label1);
panel.add(textfield1);
panel.add(label2);
panel.add(passfield);
panel.add(submit);
add(panel, BorderLayout.CENTER);
ButtonHandler handler = new ButtonHandler();
submit.addActionListener(handler);
}// end login constructor
private class ButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent arg0) {
String user = textfield1.getText();
char[] passChars = passfield.getPassword();
Connection conn = Jdbc.dbConn();
PreparedStatement ps = null;
ResultSet rs = null;
String pass = new String(passChars);
if (passChars != null) {
String sql = "SELECT employee_ID,employee_password FROM user where" +
"employee_ID='user' and employee_password=+'pass'";
try {
ps = conn.prepareStatement(sql);
ps.setString(1, user);
ps.setString(2, pass);
rs = ps.executeQuery();
if (rs.next()) {
user = rs.getString("employee_id");
pass = rs.getString("employee_password");
JOptionPane.showMessageDialog(null,"Welcome "+user);
} else {
JOptionPane.showMessageDialog(null, "Wrong Input");
}
} catch (Exception e) {
} finally {
try {
rs.close();
ps.close();
conn.close();
} catch (Exception ee) {
}
}
}// end actionPerformed
}// End ButtonHandler
}// End of class
}

you have two choices for PreparedStatement, both are correct
1) change String sql = .... definition
String sql = "SELECT employee_ID, employee_password FROM
user WHERE employee_ID = ? AND employee_password = ?";
2) put variables to the SQL statement directly
String sql = "SELECT employee_ID, employee_password FROM user WHERE
employee_ID = '" + user + "' AND employee_password = '" + pass + "'";

Change your select
employee_ID=? and employee_password=?
http://www.javaworld.com/javaworld/jw-04-2007/jw-04-jdbc.html
Or you can use named parameters
String query = "select * from people where (first_name = :name or last_name
= :name) and address = :address");
NamedParameterStatement p = new NamedParameterStatement(con, query);
p.setString("name", name);
p.setString("address", address);

please rewrite your code like this
if (passChars != null) {
String sql = "SELECT employee_ID,employee_password FROM user where
employee_ID=? and employee_password=?";
try {
ps = conn.prepareStatement(sql);
ps.setString(1, user);
ps.setString(2, pass);
rs = ps.executeQuery();
if (rs.next()) {
user = rs.getString("employee_id");
pass = rs.getString("employee_password");
JOptionPane.showMessageDialog(null,"Welcome "+user);
} else {
JOptionPane.showMessageDialog(null, "Wrong Input");
}
} catch (Exception e) {
} finally {
try {
rs.close();
ps.close();
conn.close();
} catch (Exception ee) {
}
}
}