// Tutorial 18: MicrowaveOven.java// Mimics the behavior of a microwave oven.import java.awt.*;import java.awt.event.*;import java.text.DecimalFormat;import javax.swing.*;import javax.swing.border.*;public class MicrowaveOven extends JFrame{   // JPanel for microwave window   private JPanel windowJPanel;   // JPanel for microwave controls   private JPanel controlJPanel;   // JTextField for cooking time   private JTextField displayJTextField;   // JButtons to set cooking time   private JButton oneJButton;   private JButton twoJButton;   private JButton threeJButton;   private JButton fourJButton;   private JButton fiveJButton;   private JButton sixJButton;   private JButton sevenJButton;   private JButton eightJButton;   private JButton nineJButton;   private JButton zeroJButton;   // JButtons to start and clear timer   private JButton startJButton;   private JButton clearJButton;   // Timer to count down seconds   private Timer clockTimer;   // String for storing digits entered by user   private String timeToDisplay = "";   // Time instance for storing the current time   private CookingTime microwaveTime = new CookingTime( 0, 0 );   // DecimalFormat to format time output   private DecimalFormat timeFormat = new DecimalFormat( "00" );   // no-argument constructor   public MicrowaveOven()    {      createUserInterface();   }      // create and position GUI components; register event handlers   private void createUserInterface()   {      // get content pane for attaching GUI components      Container contentPane = getContentPane();      // enable explicit positioning of GUI components      contentPane.setLayout( null );            // set up windowJPanel      windowJPanel = new JPanel();      windowJPanel.setBounds( 16, 16, 328, 205 );      windowJPanel.setBorder( new LineBorder( Color.BLACK ) );      contentPane.add( windowJPanel );            // set up controlJPanel      controlJPanel = new JPanel();      controlJPanel.setBounds( 368, 16, 149, 205 );      controlJPanel.setBorder( new LineBorder( Color.BLACK ) );      controlJPanel.setLayout( null );      contentPane.add( controlJPanel );            // set up displayJTextField      displayJTextField = new JTextField();      displayJTextField.setBounds( 7, 5, 135, 42 );      displayJTextField.setText( "Microwave Oven" );      displayJTextField.setHorizontalAlignment( JTextField.CENTER );      displayJTextField.setEditable( false );      controlJPanel.add( displayJTextField );      // set up oneJButton      oneJButton = new JButton();      oneJButton.setBounds( 13, 59, 41, 24 );      oneJButton.setText( "1" );      controlJPanel.add( oneJButton );      oneJButton.addActionListener(         new ActionListener() // anonymous inner class         {            // event handler called when oneJButton is pressed            public void actionPerformed( ActionEvent event )            {               oneJButtonActionPerformed( event );            }         } // end anonymous inner class      ); // end call to addActionListener            // set up twoJButton      twoJButton = new JButton();      twoJButton.setBounds( 54, 59, 41, 24 );      twoJButton.setText( "2" );      controlJPanel.add( twoJButton );      twoJButton.addActionListener(         new ActionListener() // anonymous inner class         {            // event handler called when twoJButton is pressed            public void actionPerformed( ActionEvent event )            {               twoJButtonActionPerformed( event );            }         } // end anonymous inner class      ); // end call to addActionListener      // set up threeJButton      threeJButton = new JButton();      threeJButton.setBounds( 95, 59, 41, 24 );      threeJButton.setText( "3" );      controlJPanel.add( threeJButton );      threeJButton.addActionListener(         new ActionListener() // anonymous inner class         {            // event handler called when threeJButton is pressed            public void actionPerformed( ActionEvent event )            {               threeJButtonActionPerformed( event );            }         } // end anonymous inner class      ); // end call to addActionListener      // set up fourJButton      fourJButton = new JButton();      fourJButton.setBounds( 13, 83, 41, 24 );      fourJButton.setText( "4" );      controlJPanel.add( fourJButton );      fourJButton.addActionListener(         new ActionListener() // anonymous inner class         {            // event handler called when fourJButton is pressed            public void actionPerformed( ActionEvent event )            {               fourJButtonActionPerformed( event );            }         } // end anonymous inner class      ); // end call to addActionListener      // set up fiveJButton      fiveJButton = new JButton();      fiveJButton.setBounds( 54, 83, 41, 24 );      fiveJButton.setText( "5" );      controlJPanel.add( fiveJButton );      fiveJButton.addActionListener(         new ActionListener() // anonymous inner class         {            // event handler called when fiveJButton is pressed            public void actionPerformed( ActionEvent event )            {               fiveJButtonActionPerformed( event );            }         } // end anonymous inner class      ); // end call to addActionListener      // set up sixJButton      sixJButton = new JButton();      sixJButton.setBounds( 95, 83, 41, 24 );      sixJButton.setText( "6" );      controlJPanel.add( sixJButton );      sixJButton.addActionListener(         new ActionListener() // anonymous inner class         {            // event handler called when sixJButton is pressed            public void actionPerformed( ActionEvent event )            {               sixJButtonActionPerformed( event );            }         } // end anonymous inner class      ); // end call to addActionListener      // set up sevenJButton      sevenJButton = new JButton();      sevenJButton.setBounds( 13, 107, 41, 24 );      sevenJButton.setText( "7" );      controlJPanel.add( sevenJButton );      sevenJButton.addActionListener(         new ActionListener() // anonymous inner class         {            // event handler called when sevenJButton is pressed            public void actionPerformed( ActionEvent event )            {               sevenJButtonActionPerformed( event );            }         } // end anonymous inner class      ); // end call to addActionListener      // set up eightJButton      eightJButton = new JButton();      eightJButton.setBounds( 54, 107, 41, 24 );      eightJButton.setText( "8" );      controlJPanel.add( eightJButton );      eightJButton.addActionListener(         new ActionListener() // anonymous inner class         {            // event handler called when eightJButton is pressed            public void actionPerformed( ActionEvent event )            {               eightJButtonActionPerformed( event );            }         } // end anonymous inner class      ); // end call to addActionListener      // set up nineJButton      nineJButton = new JButton();      nineJButton.setBounds( 95, 107, 41, 24 );      nineJButton.setText( "9" );      controlJPanel.add( nineJButton );      nineJButton.addActionListener(         new ActionListener() // anonymous inner class         {            // event handler called when nineJButton is pressed            public void actionPerformed( ActionEvent event )            {               nineJButtonActionPerformed( event );            }         } // end anonymous inner class      ); // end call to addActionListener            // set up zeroJButton      zeroJButton = new JButton();      zeroJButton.setBounds( 54, 131, 41, 24 );      zeroJButton.setText( "0" );      controlJPanel.add( zeroJButton );      zeroJButton.addActionListener(         new ActionListener() // anonymous inner class         {            // event handler called when zeroJButton is pressed            public void actionPerformed( ActionEvent event )            {               zeroJButtonActionPerformed( event );