First, this is my first time with Apache Derby. I am using netbeans, willing to use embedded apache derby, and I followed the following tutorial for configuring and installing the database. Then, I attached the derby.jar file to my project, using project properties.

<http://netbeans.org/kb/docs/ide/java-db.html#starting>

The attached image will show my database status in netbeans
![enter image description here](https://i.stack.imgur.com/ym3pf.png)

My database name is "contact". Table name is "FRIENDS".

Following is my test code

```
**DatabaseConnector.java**

import java.sql.*;

public class DataBaseConnector
{
    private Connection con;

    public DataBaseConnector()
    {

    }

    private void createConnection()
    {
        try
        {
            Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
            con = DriverManager.getConnection("jdbc:derby:C:/Users/yohan/.netbeans-derby/contact","yohan","xyz");
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }

    private void closeConnection()
    {
        try
        {
            con.close();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }

    public void insertData(int id, String firstName, String lastName)
    {
        createConnection();
        try
        {
            PreparedStatement ps = con.prepareStatement("insert into FRIENDS values(?,?,?)");
            ps.setInt(1, id);
            ps.setString(1, firstName);
            ps.setString(2, lastName);

            int result = ps.executeUpdate();

            if(result>0)
            {
                System.out.println("Data Inserted");
            }
            else
            {
                System.out.println("Something happened");
            }
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        finally
        {
            closeConnection();
        }
    }

}

```

**DatabaseUI.java**

```
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;

public class DatabaseUI extends JFrame
{
    private JLabel firstName, id, lastName;
    private JTextField idTxt, firstNameTxt, lastNameTxt;
    private JButton ok;

    public DatabaseUI()
    {
     firstName = new JLabel("First Name: ");
     lastName = new JLabel("Last Name: ");
     id = new JLabel("ID: ");

     firstNameTxt = new JTextField(10);
     lastNameTxt = new JTextField(10);
     idTxt = new JTextField(10);

     ok = new JButton("OK");
     ok.addActionListener(new OKAction());

     JPanel centerPanel = new JPanel();
     centerPanel.setLayout(new GridLayout(4,2));
     centerPanel.add(id);
     centerPanel.add(idTxt);
     centerPanel.add(firstName);
     centerPanel.add(firstNameTxt);
     centerPanel.add(lastName);
     centerPanel.add(lastNameTxt);
     centerPanel.add(new JPanel());
     centerPanel.add(ok);

     getContentPane().add(centerPanel,"Center");

     this.pack();
     this.setVisible(true);

    }

    private class OKAction implements ActionListener
    {
        public void actionPerformed(ActionEvent ae)
        {
            DataBaseConnector db = new DataBaseConnector();

            int id = Integer.parseInt(idTxt.getText());

            db.insertData(id, firstNameTxt.getText().trim(), lastNameTxt.getText().trim());
        }
    }

    public static void main(String[]args)
    {
        new DatabaseUI();
    }
}

```

But, when I am trying to insert data into the database, it is giving me the following error

```
run:
java.sql.SQLException: Failed to start database 'C:/Users/yohan/.netbeans-derby/contact' with class loader sun.misc.Launcher$AppClassLoader@1050169, see the next exception for details.
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.seeNextException(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection.bootDatabase(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection.<init>(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection30.<init>(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection40.<init>(Unknown Source)
    at org.apache.derby.jdbc.Driver40.getNewEmbedConnection(Unknown Source)
    at org.apache.derby.jdbc.InternalDriver.connect(Unknown Source)
    at org.apache.derby.jdbc.AutoloadedDriver.connect(Unknown Source)
    at java.sql.DriverManager.getConnection(DriverManager.java:579)
    at java.sql.DriverManager.getConnection(DriverManager.java:221)
    at DataBaseConnector.createConnection(DataBaseConnector.java:17)
    at DataBaseConnector.insertData(DataBaseConnector.java:40)
    at DatabaseUI$OKAction.actionPerformed(DatabaseUI.java:53)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6504)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6269)
    at java.awt.Container.processEvent(Container.java:2229)
    at java.awt.Component.dispatchEventImpl(Component.java:4860)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Component.dispatchEvent(Component.java:4686)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
    at java.awt.Container.dispatchEventImpl(Container.java:2273)
    at java.awt.Window.dispatchEventImpl(Window.java:2713)
    at java.awt.Component.dispatchEvent(Component.java:4686)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
    at java.awt.EventQueue.access$000(EventQueue.java:101)
    at java.awt.EventQueue$3.run(EventQueue.java:666)
    at java.awt.EventQueue$3.run(EventQueue.java:664)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
    at java.awt.EventQueue$4.run(EventQueue.java:680)
    at java.awt.EventQueue$4.run(EventQueue.java:678)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
Caused by: java.sql.SQLException: Failed to start database 'C:/Users/yohan/.netbeans-derby/contact' with class loader sun.misc.Launcher$AppClassLoader@1050169, see the next exception for details.
    at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(Unknown Source)
    ... 51 more
Caused by: java.sql.SQLException: Another instance of Derby may have already booted the database C:\Users\yohan\.netbeans-derby\contact.
    at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(Unknown Source)
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown Source)
    ... 48 more
Caused by: ERROR XSDB6: Another instance of Derby may have already booted the database C:\Users\yohan\.netbeans-derby\contact.
    at org.apache.derby.iapi.error.StandardException.newException(Unknown Source)
    at org.apache.derby.impl.store.raw.data.BaseDataFileFactory.privGetJBMSLockOnDB(Unknown Source)
    at org.apache.derby.impl.store.raw.data.BaseDataFileFactory.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.apache.derby.impl.store.raw.data.BaseDataFileFactory.getJBMSLockOnDB(Unknown Source)
    at org.apache.derby.impl.store.raw.data.BaseDataFileFactory.boot(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown Source)
    at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.startModule(Unknown Source)
    at org.apache.derby.iapi.services.monitor.Monitor.bootServiceModule(Unknown Source)
    at org.apache.derby.impl.store.raw.RawStore.boot(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown Source)
    at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.startModule(Unknown Source)
    at org.apache.derby.iapi.services.monitor.Monitor.bootServiceModule(Unknown Source)
    at org.apache.derby.impl.store.access.RAMAccessManager.boot(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown Source)
    at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.startModule(Unknown Source)
    at org.apache.derby.iapi.services.monitor.Monitor.bootServiceModule(Unknown Source)
    at org.apache.derby.impl.db.BasicDatabase.bootStore(Unknown Source)
    at org.apache.derby.impl.db.BasicDatabase.boot(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown Source)
    at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.bootService(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.startProviderService(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.findProviderAndStartService(Unknown Source)
    at org.apache.derby.impl.services.monitor.BaseMonitor.startPersistentService(Unknown Source)
    at org.apache.derby.iapi.services.monitor.Monitor.startPersistentService(Unknown Source)
    ... 48 more
java.lang.NullPointerException
    at DataBaseConnector.insertData(DataBaseConnector.java:43)
    at DatabaseUI$OKAction.actionPerformed(DatabaseUI.java:53)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6504)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6269)
    at java.awt.Container.processEvent(Container.java:2229)
    at java.awt.Component.dispatchEventImpl(Component.java:4860)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Component.dispatchEvent(Component.java:4686)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
    at java.awt.Container.dispatchEventImpl(Container.java:2273)
    at java.awt.Window.dispatchEventImpl(Window.java:2713)
    at java.awt.Component.dispatchEvent(Component.java:4686)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
    at java.awt.EventQueue.access$000(EventQueue.java:101)
    at java.awt.EventQueue$3.run(EventQueue.java:666)
    at java.awt.EventQueue$3.run(EventQueue.java:664)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
    at java.awt.EventQueue$4.run(EventQueue.java:680)
    at java.awt.EventQueue$4.run(EventQueue.java:678)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
java.lang.NullPointerException
    at DataBaseConnector.closeConnection(DataBaseConnector.java:29)
    at DataBaseConnector.insertData(DataBaseConnector.java:65)
    at DatabaseUI$OKAction.actionPerformed(DatabaseUI.java:53)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6504)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6269)
    at java.awt.Container.processEvent(Container.java:2229)
    at java.awt.Component.dispatchEventImpl(Component.java:4860)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Component.dispatchEvent(Component.java:4686)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
    at java.awt.Container.dispatchEventImpl(Container.java:2273)
    at java.awt.Window.dispatchEventImpl(Window.java:2713)
    at java.awt.Component.dispatchEvent(Component.java:4686)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
    at java.awt.EventQueue.access$000(EventQueue.java:101)
    at java.awt.EventQueue$3.run(EventQueue.java:666)
    at java.awt.EventQueue$3.run(EventQueue.java:664)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
    at java.awt.EventQueue$4.run(EventQueue.java:680)
    at java.awt.EventQueue$4.run(EventQueue.java:678)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
BUILD SUCCESSFUL (total time: 12 seconds)

```

Why is this? Please help!

Apart from that first main question, I would like to ask another 2 questions.

2. I have to give the explicit location of the database as the connection here. But, when I give this to a client, how can I do that?
3. I have to start the database connection manually using netbeans. Is there anyway to start the database connection automatically? Using code?

Please help me. Thanks