Java JDBC help

[nick2price]

I am really not getting any further with this, so frustrating. I have a DatabaseUtils class

public class DatabaseUtils
{
public static final String DRIVER = "oracle.jdbc.driver.OracleDriver";
public static final String URL = "jdbc:oracle:thin:@localhost:1521:XE";
public static final String USERNAME = "rory";
public static final String PASSWORD = "macflid";

private Connection connection;

public static void main(String[] args)
{
Connection connection = null;
try
{
if (args.length > 0)
{
connection = DatabaseUtils.connect(DRIVER, URL, USERNAME, PASSWORD);
DatabaseUtils utils = new DatabaseUtils(connection);

}
else
{
System.out.println("Usage: DatabaseUtils <sql query>");
}
}
catch (Exception e)
{
e.printStackTrace();
}
finally
{
close(connection);
}
}

public DatabaseUtils(Connection connection)
{
this.connection = connection;
}

public static Connection connect(String driver, String url, String username, String password) throws ClassNotFoundException, SQLException
{
Class.forName(driver);
return DriverManager.getConnection(url, username, password);
}

public static void close(Connection connection)
{
try
{
if (connection != null)
{
connection.close();
}
}
catch (SQLException e)
{
e.printStackTrace();
}
}

public static void close(Statement statement)
{
try
{
if (statement != null)
{
statement.close();
}
}
catch (SQLException e)
{
e.printStackTrace();
}
}

public static void close(ResultSet resultSet)
{
try
{
if (resultSet != null)
{
resultSet.close();
}
}
catch (SQLException e)
{
e.printStackTrace();
}
}

public static void rollback(Connection connection)
{
try
{
if (connection != null)
{
connection.rollback();
}
}
catch (SQLException e)
{
e.printStackTrace();
}
}
}

Then i am trying to get another class create the connection to pass it to my DAO clas

import java.util.*;
import java.sql.*;

class PersonService
{
private PersonDAO personDao;
public static final String DRIVER = "oracle.jdbc.driver.OracleDriver";
public static final String URL = "jdbc:oracle:thin:@localhost:1521:XE";
public static final String USERNAME = "rory";
public static final String PASSWORD = "macflid";

public PersonService(PersonInfo p)
{
Connection c = null;

try
{
c = DatabaseUtils.connect(DRIVER, URL, USERNAME, PASSWORD);
c.setAutoCommit(false);
personDao.setConnection(c);
personDao.savePerson(p);
c.commit();
}
catch (Exception e)
{
DatabaseUtils.rollback(c);
e.printStackTrace();
}
finally
{
DatabaseUtils.close(c);
}
}
}

Then in my DAO class i am trying to do an isert query

public class PersonDAO{ 

private Connection con;

public void setConnection(Connection c)
{
con=c;
}

public void savePerson(PersonInfo person)
{
try
{

String sql = "INSERT INTO Person(name, idNo, " +
"userName, passWord) VALUES (?,?,?,?) ";

// Create a Preparedstatement
PreparedStatement ps = con.prepareStatement(sql);

ps.setString(1, person.getName());
ps.setString(2, person.getIdNo());
ps.setString(3, person.getUsername());
ps.setString(4, person.getPassword());

ps.executeUpdate();
}

catch(Exception e)
{
System.out.println(e);
}

}

Nothing is being inputted into my database. I have just really confused myself. Can anyone see where i am going wrong? i am being return at runtime a NullPointerException.
cheers

[pao]

Can you print the stack trace relating to the null pointer exception please?

[nick2price]

I would if i knew where the exception was coming from. I have lots of different classes and methods that i have no idea where its from. The only thing i do know is that it must be coming from recieving an empty connection object when i setConnection in my personDao class

[nick2price]

manage to find where the exception was, here is the stacktrace

java.lang.NullPointerException
java.lang.NullPointerException
        at PersonDAO.savePerson(PersonDAO.java:22)
        at Register.save(Register.java:196)
        at Register.actionPerformed(Register.java:166)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:19
95)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.jav
a:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel
.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242
)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonL
istener.java:236)
        at java.awt.Component.processMouseEvent(Component.java:6041)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
        at java.awt.Component.processEvent(Component.java:5806)
        at java.awt.Container.processEvent(Container.java:2058)
        at java.awt.Component.dispatchEventImpl(Component.java:4413)
        at java.awt.Container.dispatchEventImpl(Container.java:2116)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322
)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3986)

        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3916)
        at java.awt.Container.dispatchEventImpl(Container.java:2102)
        at java.awt.Window.dispatchEventImpl(Window.java:2440)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThre
ad.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.
java:183)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThre
ad.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)

        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)

        at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)
Press any key to continue...

Would you able to tell me how to fix my code from this?
cheers

[masijade]

the "person" you pass to the method savePerson is null.

[nick2price]

So it has nothing to do with my connection passing?

[masijade]

Well, it could be that, as well, but it would help to know exactly which line is line 22 in PersonDAO.java, as indicated by the stacktrace

at PersonDAO.savePerson(PersonDAO.java:22)