Thread: converter program, problem with action listener

here is my operater class and i am having trouble at line 92 and 215... it gives me the error:
<anonymous operator$1> is not abstract and does not override abstract method actionPerformed(java.awt.event.ActionEvent) in java.awt.event.ActionListener

   import java.awt.*;
   import javax.swing.*;
   import java.awt.event.*;
   import java.util.*;
   import java.io.*;
   import javax.swing.event.*;
 
    public class operator
   {
      private Container c;
      ConvertArray conArr;
      JComboBox length1, length2, volume1, volume2, mass1, mass2, tempurate1, tempurate2, currency1, currency2;
 
      String first, second;
      int num = 0;
 
      JButton Ok = new JButton ("Convert");
      JButton cancel = new JButton ("cancel");
 
      JFrame ConLength = new JFrame ("converting length");
      JFrame ConVolume = new JFrame ("Converting Volume");
 
 
 
       public operator (ConvertArray i)
      {
         conArr = i;
      }
 
       public void Length () 
      {
 
 
         ConLength.setSize (500,400);
         ConLength.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
         ConLength.setVisible (true);
 
         JLabel addinfo = new JLabel ("Please select the first box for the value you are going to enter");
         JLabel addinfo2 = new JLabel ("select the second value for the value you want to convert to");
         JLabel addinfo3 = new JLabel ("Then click ok");	
         JLabel addinfo4 = new JLabel ("enter here:");
 
         length1 = new JComboBox ();
         length1.addItem ("cm");
         length1.addItem ("inch");
         length1.addItem ("feet");
         length1.addItem ("meters");
         length1.setBounds (70, 130, 150, 20);
 
 
         length2 = new JComboBox ();
         length2.addItem ("cm");
         length2.addItem ("inch");
         length2.addItem ("feet");
         length2.addItem ("meters");  
         length2.setBounds (250, 130, 150, 20);
 
 
         final JTextArea enter = new JTextArea (20, 130);
         enter.setBounds (250, 200, 150, 20); 
 
 
         addinfo.setBounds (10, 5, 400, 20);
         addinfo2.setBounds (10, 25, 400, 20);
         addinfo3.setBounds (10, 45, 400, 20);
         addinfo4.setBounds (70,200,150,20);
 
 
 
         Ok.setBounds (100, 275, 100, 50);
         cancel.setBounds (250, 275, 100, 50);
 
 
         c = ConLength.getContentPane ();
 
         c.setLayout (null);
 
         c.add(addinfo);
         c.add(addinfo2);
         c.add(addinfo3);  
         c.add (addinfo4);
         c.add(length1);
         c.add(length2);
         c.add(enter);
         c.add(Ok);
         c.add(cancel);
 
         ConLength.setVisible (true);    
 
 
         Ok.addActionListener (
                new ActionListener()
               {
 
                   public void itemStateChange (ItemEvent event, ItemEvent event2)
                  {
 
                     first = event.getItem ().toString ();
                     second = event2.getItem ().toString ();
 
 
                     ConLength.dispose ();
 
                  }
 
 
                   public void ActionPerformed (ActionEvent event)
                  {
                     String a = enter.getText ();
                     num = Integer.parseInt (a);
 
 
                     if ( first == "length")
                     {
 
 
 
                     }
 
 
 
 
                  }
               }
 
            );
 
 
 
         cancel1 (); 
      }
 
       private void cancel1 ()
      {
         cancel.addActionListener (
                new ActionListener ()
               {
                   public void actionPerformed (ActionEvent event)
                  {
                     ConLength.dispose ();
                  }
               }
 
 
            );
      }
 
 
 
   	// to convert voulme
 
 
       public void Voulme () 
      {
 
 
         ConVolume.setSize (500,400);
         ConVolume.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
         ConVolume.setVisible (true);
 
         JLabel addinfo = new JLabel ("Please select the first box for the value you are going to enter");
         JLabel addinfo2 = new JLabel ("select the second value for the value you want to convert to");
         JLabel addinfo3 = new JLabel ("Then click ok");	
         JLabel addinfo4 = new JLabel ("enter here:");
 
         volume1 = new JComboBox ();
         volume1.addItem ("Litres");
         volume1.addItem ("Gallons");
         volume1.addItem ("Oz.");
         volume1.addItem ("Millilitres");
         volume1.setBounds (70, 130, 150, 20);
 
 
         volume2 = new JComboBox ();
         volume2.addItem ("Litres");
         volume2.addItem ("Gallons");
         volume2.addItem ("Oz.");
         volume2.addItem ("Millilitres");  
         volume2.setBounds (250, 130, 150, 20);
 
 
         final JTextArea enter = new JTextArea (20, 130);
         enter.setBounds (250, 200, 150, 20); 
 
 
         addinfo.setBounds (10, 5, 400, 20);
         addinfo2.setBounds (10, 25, 400, 20);
         addinfo3.setBounds (10, 45, 400, 20);
         addinfo4.setBounds (70,200,150,20);
 
 
 
         Ok.setBounds (100, 275, 100, 50);
         cancel.setBounds (250, 275, 100, 50);
 
 
         c = ConVolume.getContentPane ();
 
         c.setLayout (null);
 
         c.add(addinfo);
         c.add(addinfo2);
         c.add(addinfo3);  
         c.add (addinfo4);
         c.add(length1);
         c.add(length2);
         c.add(enter);
         c.add(Ok);
         c.add(cancel);
 
         ConVolume.setVisible (true);    
 
 
         Ok.addActionListener (
                new ActionListener()
               {
 
                   public void itemStateChange (ItemEvent event, ItemEvent event2)
                  {
 
                     first = event.getItem ().toString ();
                     second = event2.getItem ().toString ();
 
                  }
 
 
                   public void ActionPerformed (ActionEvent event)
                  {
                     String a = enter.getText ();
                     num = Integer.parseInt (a);
 
 
                     if ( first == "Litres")
                     {
 
 
 
 
                     }
 
 
                     ConVolume.dispose ();
 
                  }
               }
 
            );
 
         cancel2 (); 
      }
 
       private void cancel2 ()
      {
         cancel.addActionListener (
                new ActionListener ()
               {
                   public void actionPerformed (ActionEvent event)
                  {
                     ConVolume.dispose ();
                  }
               }
 
            );
      }
   }

Here is the running class:

 
   import java.io.*;
   import java.awt.*;
   import javax.swing.*;
   import java.awt.event.*;
   import java.util.*;
   import javax.swing.event.*;
 
 
    public class ConverterMenu extends JFrame implements ActionListener
   {
 
      private JMenu converterMenu, helpMenu, exitMenu;
      private JMenuItem Volume, length, mass, temperature, currency, Help, About, Exit;
 
      private JButton convert1,convert2,convert3;
      private Container contentArea;
 
      ConvertArray Ia = new ConvertArray ();
 
 
       ConverterMenu()  throws IOException
      {
 
 
 
         super ("Convert 9.0");
         setSize (400,500);
         setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
         setVisible (true);
 
         contentArea = getContentPane ();  
         contentArea.setLayout (null);
 
         ImageIcon scale = new ImageIcon ("scale2.gif");
         JLabel labelpic = new JLabel (scale);
         labelpic.setBounds (90, 10, 220, 170);
         contentArea.add (labelpic);
 
 
         convert1 = new JButton ("Convert Length");
         convert2 = new JButton ("Convert Volume");
         convert3 = new JButton ("Convert Currency");
 
         convert1.setBounds (100,200,200,50);
         convert2.setBounds (100,270,200,50);
         convert3.setBounds (100,340,200,50);
 
         convert1.addActionListener (this);
         convert2.addActionListener (this);
         convert3.addActionListener (this);
 
         contentArea.add(convert1);     
         contentArea.add(convert2);         
         contentArea.add(convert3);
 
 
         setContentPane (contentArea);
 
      	//adding items to the arrays from the files
 
         Ia.addItems (); 
 
      	// creating the drop down menu
 
 
         JMenuBar menuBar = new JMenuBar ();
         setJMenuBar (menuBar);
 
 
 
         converterMenu = new JMenu ("Convert");
         converterMenu.setMnemonic ('C');
         menuBar.add (converterMenu);
 
         helpMenu = new JMenu ("Help");
         helpMenu.setMnemonic ('H');
         menuBar.add (helpMenu);
 
         exitMenu = new JMenu ("Exit");
         exitMenu.setMnemonic ('X');
         menuBar.add (exitMenu);
 
         setMenuItems ();
 
         setVisible (true);
         setResizable (false);
 
      }
 
       public void actionPerformed (ActionEvent e)
      {
 
         if (e.getActionCommand ().equals ("Convert Length"))
         {
            try
            { 
 
               operator op = new operator (Ia);
               op.Length ();
 
            }
                catch (Exception exp)
               {
               }
 
         }
 
      }
 
 
       private void setMenuItems ()
      {
 
         Volume = new JMenuItem ("Volume");
         Volume.setMnemonic ('o');
         //Volume.addActionListener (this);
         converterMenu.add(Volume);
 
         length = new JMenuItem ("Length");
         converterMenu.addSeparator ();
         length.setMnemonic ('L');
         length.addActionListener (this);
         converterMenu.add(length);
 
         mass = new JMenuItem ("Mass");
         converterMenu.addSeparator ();
         mass.setMnemonic ('M');
         //mass.addActionListener (this);
         converterMenu.add(mass);
 
         temperature = new JMenuItem ("Temperature");
         converterMenu.addSeparator ();
         temperature.setMnemonic ('T');
         //temperature.addActionListener (this);
         converterMenu.add(temperature);
 
         currency = new JMenuItem ("Currency");
         converterMenu.addSeparator ();
         currency.setMnemonic ('C');
      	//currency.addActionListener (this);
         converterMenu.add(currency);
 
         Help = new JMenuItem ("Help Menu");
      	//Help.addActionListener (this);
         Help.setMnemonic ('H');
         helpMenu.add (Help);
 
         About = new JMenuItem ("About prog.");
         About.setMnemonic ('A');
         helpMenu.add (About);
 
         Exit = new JMenuItem ("Exit");
         Exit.setMnemonic ('X');
         exitMenu.add (Exit);
 
      }
 
 
       public static void main (String [] args) throws IOException
      {
         new ConverterMenu ();
      }
 
   }

im having a problem the Ok.addActionListener

please help