Override Abstract Methods in NetBeans 6.1

I just upgraded to NetBeans 6.1 and I can't figure out how to automatically override abstract methods... I I know in older versions you could select a menu option and select abstract methods and NetBeans would put them all in for you...

I'm sorry... I admit that I only looked quickly for a NetABeans forum and didn't find one... What is it under so I know for the future...

Similar Messages

Is not abstract and does not override abstract method actionPerformed

I dont how to corr. Please help!! and thank you very much!!
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class test extends JFrame implements ActionListener, ItemListener
          private CenterPanel centerPanel;
          private QuestionPanel questionPanel;
          private ButtonPanel buttonPanel;
          private ResponsePanel responsePanel;
          private JButton b1,b2,b3,b4,b5;               //Create five references to Jbutton instances
     private JTextField t1,t2,t3,t4,t5;          //Create five references to JTextField instances
          private JLabel label1;                    //Create one references to JLabel instances
          private JRadioButton q1,q2,q3;               //Create three references to JRadioButton instances
          private ButtonGroup radioGroup;               //Create one references to Button Group instances
          private int que1[] = new int[5];           //Create int[4] Array
          private int que2[] = new int[5];
          private int que3[] = new int[5];
          private String temp1, temp2, temp3, temp4, temp5, temp6, temp7, temp8, temp9, temp10,
                    temp11, temp12, temp13, temp14, temp15;
public test (String header)
          super(header);
          Container container = getContentPane();
          label1 = new JLabel ("PLease click on your response to ");
          q1 = new JRadioButton("I understand most of the content of this subject",true);
          add(q1);
          q2 = new JRadioButton("I see the relevance of the subject to my degree",false);
          add(q2);
          q3 = new JRadioButton("The workload in this subject is appropriate",false);
          add(q3);
          radioGroup = new ButtonGroup();               //JRadioButton belong to ButtonGroup
          radioGroup.add(q1);
          radioGroup.add(q2);
          radioGroup.add(q3);
          JPanel buttonPanel = new JPanel();
          JPanel responsePanel = new JPanel();
          JPanel questionPanel = new JPanel();
          JPanel centerPanel = new JPanel();
          b1 = new JButton ("Strongly DISAGREE");          //Instantiate JButton with text
          b1.addActionListener (this);               //Register JButtons to receive events
          b2 = new JButton ("DISAGREE");
          b2.addActionListener (this);
          b3 = new JButton ("Neither AGREE or DISAGREE");
          b3.addActionListener (this);
          b4 = new JButton ("AGREE");
          b4.addActionListener (this);
          b5 = new JButton ("Strongly AGREE");
          b5.addActionListener (this);
          buttonPanel.setLayout(new GridLayout(5,1));
          buttonPanel.add(b1);
          buttonPanel.add(b2);
          buttonPanel.add(b3);
          buttonPanel.add(b4);
          buttonPanel.add(b5);
          t1 = new JTextField ("0",3);               //JTextField contains empty string
          t2 = new JTextField ("0",3);
          t3 = new JTextField ("0",3);
          t4 = new JTextField ("0",3);
          t5 = new JTextField ("0",3);
          t1.setEditable( false );
          t2.setEditable( false );
          t3.setEditable( false );
          t4.setEditable( false );
          t5.setEditable( false );
          responsePanel.setLayout(new GridLayout(5,1));
          responsePanel.add(t1);
          responsePanel.add(t2);
          responsePanel.add(t3);
          responsePanel.add(t4);
          responsePanel.add(t5);
          questionPanel.setLayout(new GridLayout(4,1));
          questionPanel.add(label1);
          questionPanel.add(q1);
          questionPanel.add(q2);
          questionPanel.add(q3);
          centerPanel.add(buttonPanel,BorderLayout.CENTER);
          centerPanel.add(responsePanel,BorderLayout.EAST);
          container.add(centerPanel,BorderLayout.WEST);
          container.add(questionPanel,BorderLayout.NORTH);
          q1.addActionListener(
               new ActionListener(){
          public void actionPerformed( ActionEvent e )
{                                        //actionPerformed of all registered listeners
          if (e.getSource() == b1) {
               que1[0] = Integer.parseInt(t1.getText()) + 1;
               String temp1 = String.valueOf(que1[0]);
          t1.setText(temp1);
          else if (e.getSource() == b2)     {
               que1[1] = Integer.parseInt(t2.getText()) + 1;
               String temp2 = String.valueOf(que1[1]);
          t2.setText(temp2);
          else if (e.getSource() == b3)     {
               que1[2] = Integer.parseInt(t3.getText()) + 1;
               String temp3 = String.valueOf(que1[2]);
          t3.setText(temp3);
          else if (e.getSource() == b4)     {
               que1[3] = Integer.parseInt(t4.getText()) + 1;
               String temp4 = String.valueOf(que1[3]);
          t4.setText(temp4);
          else if (e.getSource() == b5)     {
               que1[4] = Integer.parseInt(t5.getText()) + 1;
               String temp5 = String.valueOf(que1[4]);
          t5.setText(temp5);
} //end action performed
          q2.addActionListener(
               new ActionListener(){
          public void actionPerformed( ActionEvent e )
{                                        //actionPerformed of all registered listeners
          if (e.getSource() == b1) {
               que2[0] = Integer.parseInt(t1.getText()) + 1;
               String temp6 = String.valueOf(que2[0]);
          t1.setText(temp1);
          else if (e.getSource() == b2)     {
               que2[1] = Integer.parseInt(t2.getText()) + 1;
               String temp7 = String.valueOf(que2[1]);
          t2.setText(temp7);
          else if (e.getSource() == b3)     {
               que2[2] = Integer.parseInt(t3.getText()) + 1;
               String temp8 = String.valueOf(que2[2]);
          t3.setText(temp8);
          else if (e.getSource() == b4)     {
               que2[3] = Integer.parseInt(t4.getText()) + 1;
               String temp9 = String.valueOf(que2[3]);
          t4.setText(temp9);
          else if (e.getSource() == b5)     {
               que2[4] = Integer.parseInt(t5.getText()) + 1;
               String temp10 = String.valueOf(que2[4]);
          t5.setText(temp10);
} //end action performed
          q3.addActionListener(
               new ActionListener(){
          public void actionPerformed( ActionEvent e )
{                                        //actionPerformed of all registered listeners
          if (e.getSource() == b1) {
               que3[0] = Integer.parseInt(t1.getText()) + 1;
               String temp11 = String.valueOf(que3[0]);
          t1.setText(temp11);
          else if (e.getSource() == b2)     {
               que3[1] = Integer.parseInt(t2.getText()) + 1;
               String temp12 = String.valueOf(que3[1]);
          t2.setText(temp12);
          else if (e.getSource() == b3)     {
               que3[2] = Integer.parseInt(t3.getText()) + 1;
               String temp13 = String.valueOf(que3[2]);
          t3.setText(temp13);
          else if (e.getSource() == b4)     {
               que3[3] = Integer.parseInt(t4.getText()) + 1;
               String temp14 = String.valueOf(que3[3]);
          t4.setText(temp14);
          else if (e.getSource() == b5)     {
               que3[4] = Integer.parseInt(t5.getText()) + 1;
               String temp15 = String.valueOf(que3[4]);
          t5.setText(temp15);
} //end action performed
}//end constructor test
public void itemStateChanged(ItemEvent item) {
//int state = item.getStateChange();
//if (q1 == item.SELECTED)
          public class ButtonPanel extends JPanel
               public ButtonPanel()
          public class CenterPanel extends JPanel
               public CenterPanel()
          public class QuestionPanel extends JPanel
               public QuestionPanel()
          public class ResponsePanel extends JPanel
               public ResponsePanel()
public static void main(String [] args)
     test surveyFrame = new test("Student Survey") ;
     surveyFrame.setSize( 500,300 );
     surveyFrame.setVisible(true);
     surveyFrame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
     }//end main
}//end class test

is not abstract and does not override abstract method actionPerformed
Oh, I see that the title of your post is an error message? Ok. Well, the test class is declared as implementing an ActionListener. That means the test class must have an actionPerformed() method. Your test class apparently does not.
It does not appear that the test class needs to implement ActionListener. You are using annonymous classes as listeners.

Is not abstract and does not override abstract method tablechanged

I will remove all the gui code to make it shorter, but my problem lies with my InteractiveTableModelListener.
public class Meet extends JPanel{
private static void createAndShowGUI() {
        JFrame frame = new JFrame("MEET_dataTable");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new Meet(), BorderLayout.CENTER);
        frame.pack();
        frame.setVisible(true);
public class InteractiveTableModelListener implements TableModelListener {
     public void TableChanged(TableModelEvent evt) {
if (evt.getType() == TableModelEvent.UPDATE) {
      int column = evt.getColumn();
      int row = evt.getFirstRow();
      dataTable.setColumnSelectionInterval(column + 1, column + 1);
      dataTable.setRowSelectionInterval(row, row);
class InteractiveRenderer extends DefaultTableCellRenderer {
protected int interactiveColumn;
public InteractiveRenderer(int interactiveColumn) {
      this.interactiveColumn = interactiveColumn;
public Component getTableCellRendererComponent(JTable dataTable,
     Object value, boolean isSelected, boolean hasFocus, int row,
     int column)
Component c = super.getTableCellRendererComponent(dataTable, value, isSelected, hasFocus, row, column);
   if (column == interactiveColumn && hasFocus) {
     if ((Meet.this.tableModel.getRowCount() - 1) == row &&
        !Meet.this.tableModel.hasEmptyRow())
         Meet.this.tableModel.addEmptyRow();
    highlightLastRow(row);
return c;
public void highlightLastRow(int row) {
     int lastrow = tableModel.getRowCount();
if (row == lastrow - 1) {
      dataTable.setRowSelectionInterval(lastrow - 1, lastrow - 1);
else {
      dataTable.setRowSelectionInterval(row + 1, row + 1);
     dataTable.setColumnSelectionInterval(0, 0);
public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
            UIManager.put("swing.boldMetal", Boolean.FALSE);
            createAndShowGUI();
}As i say, i have removed all the gui code to make it shorter, but in this code i create the table and add all the model to it. I am being returned with the error
Meet.InteractiveTableModelListener is not abstract and does not override abstract method tableChanged(javax.swing.event.TableModelEvent)in javax.swing.event.TableModelListener
what would be causing this error?
Cheers

Sorry, just figured out my silly error, the method is tableChanged not TableChanged.
cheers
TOPIC CLOSED
Edited by: nick2price on Sep 11, 2008 7:08 AM

Is not abstract and does not override abstract method ERROR

Hello. I'm new at all this, and am attempting to recreate a sample code out of my book (Teach Yourself XML in 24 Hours), and I keep getting an error. I appriciate any help.
This is the Error that I get:
DocumentPrinter is not abstract and does not override abstract method skippedEntity(java.lang.String) in org.xml.sax.ContentHandler
public class DocumentPrinter implements ContentHandler, ErrorHandler
        ^This is the sourcecode:
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.ErrorHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXParseException;
import org.xml.sax.XMLReader;
public class DocumentPrinter implements ContentHandler, ErrorHandler
// A Constant containing the name of the SAX parser to use.
private static final String PARSER_NAME = "org.apache.xerces.parsers.SAXParser";
public static void main(String[] args)
   // Check to see whether the user supplied any command line arguments. If not, print an error and exit.
   if (args.length == 0)
     System.out.println("No XML document path specified.");
     System.exit(1);
   // Create a new instance of the DocumentPrinter class.
   DocumentPrinter dp = new DocumentPrinter();
   try
     // Create a new instance of the XML Parser.
     XMLReader parser = (XMLReader)Class.forName(PARSER_NAME).newInstance();
     // Set the parser's content handler
    // parser.setContentHandler(dp);
     // Set the parsers error handler
     parser.setErrorHandler(dp);
     // Parse the file named in the argument
     parser.parse(args[0]);
   catch (Exception ex)
     System.out.println(ex.getMessage());
     ex.printStackTrace();
public void characters(char[] ch, int start, int length)
   String chars ="";
   for (int i = start; i < start + length; i++)
     chars = chars + ch;
System.out.println("Recieved characters: " + chars);
public void startDocument()
System.out.println("Start Document.");
public void endDocument()
System.out.println("End of Document.");
public void startElement(String namespaceURI, String localName, String qName, Attributes atts)
System.out.println("Start element: " + localName);
for (int i = 0; i < atts.getLength(); i++)
System.out.println(" Attribute: " + atts.getLocalName(i));
System.out.println(" Value: " + atts.getValue(i));
public void endElement(String namespaceURI, String localName, String qName)
System.out.println("End of element: " + localName);
public void startPrefixMapping(String prefix, String uri)
System.out.println("Prefix mapping: " + prefix);
System.out.println("URI: " + uri);
public void endPrefixMapping(String prefix)
System.out.println("End of prefix mapping: " + prefix);
public void ignorableWhitespace(char[] ch, int start, int length)
System.out.println("Recieved whitespace.");
public void processingInstruction(String target, String data)
System.out.println("Recieved processing instruction:");
System.out.println("Target: " + target);
System.out.println("Data: " + data);
public void setDocumentLocation(Locator locator)
// Nada
public void error(SAXParseException exception)
System.out.println("Parsing error on line " + exception.getLineNumber());
public void fatalError(SAXParseException exception)
System.out.println("Fatal parsing error on line " + exception.getLineNumber());
public void warning(SAXParseException exception)
System.out.println("Warning on line " + exception.getLineNumber());

Check to make sure that the arguments are consistent with your ContentHandler class. Probably the wrong type.
I think you forgot to include the skippedEntity method, it seems to be missing. Even if an implemented class has a method that you are not using, you still have to include the method in your code even if it doesn't do anything.
Message was edited by:
ChargersTule1

...is not abstract and does not override abstract method compare

Why am I getting the above compile error when I am very clearly overriding abstract method compare (ditto abstract method compareTo)? Here is my code -- which was presented 1.5 code and I'm trying to retrofit to 1.4 -- followed by the complete compile time error. Thanks in advance for your help (even though I'm sure this is an easy question for you experts):
import java.util.*;
   This program sorts a set of item by comparing
   their descriptions.
public class TreeSetTest
   public static void main(String[] args)
      SortedSet parts = new TreeSet();
      parts.add(new Item("Toaster", 1234));
      parts.add(new Item("Widget", 4562));
      parts.add(new Item("Modem", 9912));
      System.out.println(parts);
      SortedSet sortByDescription = new TreeSet(new
         Comparator()
            public int compare(Item a, Item b)   // LINE CAUSING THE ERROR
               String descrA = a.getDescription();
               String descrB = b.getDescription();
               return descrA.compareTo(descrB);
      sortByDescription.addAll(parts);
      System.out.println(sortByDescription);
   An item with a description and a part number.
class Item implements Comparable
      Constructs an item.
      @param aDescription the item's description
      @param aPartNumber the item's part number
   public Item(String aDescription, int aPartNumber)
      description = aDescription;
      partNumber = aPartNumber;
      Gets the description of this item.
      @return the description
   public String getDescription()
      return description;
   public String toString()
      return "[descripion=" + description
         + ", partNumber=" + partNumber + "]";
   public boolean equals(Object otherObject)
      if (this == otherObject) return true;
      if (otherObject == null) return false;
      if (getClass() != otherObject.getClass()) return false;
      Item other = (Item) otherObject;
      return description.equals(other.description)
         && partNumber == other.partNumber;
   public int hashCode()
      return 13 * description.hashCode() + 17 * partNumber;
   public int compareTo(Item other)   // OTHER LINE CAUSING THE ERROR
      return partNumber - other.partNumber;
   private String description;
   private int partNumber;
}Compiler error:
TreeSetTest.java:25: <anonymous TreeSetTest$1> is not abstract and does not over
ride abstract method compare(java.lang.Object,java.lang.Object) in java.util.Com
parator
            public int compare(Item a, Item b)
                       ^
TreeSetTest.java:41: Item is not abstract and does not override abstract method
compareTo(java.lang.Object) in java.lang.Comparable
class Item implements Comparable
^
2 errors

According to the book I'm reading, if you merely take
out the generic from the code, it should compile and
run in v1.4 (assuming, of course, that the class
exists in 1.4). I don't know what book you are reading but that's certainly incorrect or incomplete at least. I've manually retrofitted code to 1.4, and you'll be inserting casts as well as replacing type references with Object (or the erased type, to be more precise).
These interfaces do exist in 1.4, and
without the generics.Exactly. Which means compareTo takes an Object, and you should change your overriding method accordingly.
But this raises a new question: how does my 1.4
compiler know anything about generics? It doesn't and it can't. As the compiler is telling you, those interfaces expect Object. Think about it, you want to implement one interface which declares a method argument type of Object, in several classes, each with a different type. Obviously all of those are not valid overrides.

Product is not abstract and does not override abstract method

Received the following errors.
Product.java:3: Product is not abstract and does not override abstract method ge
tDisplayText() in Displayable
public class Product implements Displayable
^
Product.java:16: getDisplayText() in Product cannot implement getDisplayText() i
n Displayable; attempting to use incompatible return type
found : void
required: java.lang.String
public void getDisplayText()
^
2 errors
Code reads as follows
import java.text.NumberFormat;
public class Product implements Displayable
     private String code;
     private String description;
     private double price;
     public Product()
          this.code = "";
          this.description = "";
          this.price = 0;
public void getDisplayText()
String message =
"Code: " + code + "\n" +
"Description: " + description + "\n" +
"Price: " + this.getFormattedPrice() + "\n";
     public Product(String code, String description, double price)
          this.code = code;
          this.description = description;
          this.price = price;
     public void setCode(String code)
          this.code = code;
     public String getCode(){
          return code;
     public void setDescription(String description)
          this.description = description;
     public String getDescription()
          return description;
     public void setPrice(double price)
          this.price = price;
     public double getPrice()
          return price;
     public String getFormattedPrice()
          NumberFormat currency = NumberFormat.getCurrencyInstance();
          return currency.format(price);
Please help!

Received the following errors.
Product.java:3: Product is not abstract and does not
override abstract method ge
tDisplayText() in Displayable
public class Product implements Displayable
^
Product.java:16: getDisplayText() in Product cannot
implement getDisplayText() i
n Displayable; attempting to use incompatible return
type
found : void
required: java.lang.String
public void getDisplayText()
^
2 errors
Code reads as follows
Please use the code tags when posting code. There is a code button right above the text box where you enter your post. Click on it and put the code between the code tags.
These error messages are quite clear in telling what is wrong. You have an Interface called Displayable that specifies a method something like thispublic String getDisplayText() {But in your Product source code, you created thismethodpublic void getDisplayText() {The compiler is complaining because the methods are not the same.
You also need to return a String in the method probalby like thisreturn message;

Overriding abstract methods with generic argument

Hi,
This post is similar to the one posted just before it :
[http://forum.java.sun.com/thread.jspa?threadID=5281500|http://forum.java.sun.com/thread.jspa?threadID=5281500]
I am trying to override an abstract method which has a generic argument and a problem occurs. I would like to find out whether what I am trying to do is not legal. The point of interest here is that the overriding class reduces the scope of the abstract class.
The Abstract class AbstractAdapter defines accessors for a collection containing objects derived from AbstractPort. (<? extends AbstractPort>)
The overriding class Adapter overrides these accessors but reduces the scope of the collection objects from <? extends AbstractPort> to <Port>. Port
Here is my abstract class:
public abstract class AbstractAdapter {
     public abstract Collection<? extends AbstractPort> getPorts();
     public abstract void setPorts(Collection<? extends AbstractPort> ports);
}And here is the class that overrides it:
public class Adapter extends AbstractAdapter {
     public Collection<Port> getPorts() {
          return null;
     public void setPorts(Collection<Port> ports) {
}The Port class is shown here:
public class Port extends AbstractPort {
}Edited by: BenDave on Apr 2, 2008 4:39 AM

It's not really the same.
I don't have a compiler to hand, so this is off the top of my head. I expect you want something like this:
public abstract class AbstractAdapter<T extends AbstractPort> {
     public abstract Collection<T> getPorts();
     public abstract void setPorts(Collection<T> ports);
public class Adapter extends AbstractAdapter<Port> {
     public Collection<Port> getPorts() {
          return null;
     public void setPorts(Collection<Port> ports) {
}

..is not abstract and does not override abstract method..

Hello,
I've been creating a GUI from scratch, up to now, i have managed to successfully compile the code which forms the window, and a JMenu bar. I now need to add buttons, and for this i need to use an ActionListener, but when i put "implements ActionListener" at the end of "public class TestCode extends JFrame", i recieve the above error message (abstract..). I've looked at recent posts and have come across a post that says adding "actionPerformed(java.awt.event.ActionEvent e)" to the class will resolve the issue. When i add that, i recieve a compile error message saying to add '{' after actionPerformed. I've done this however it still does not compile. Can anyone point me in the right direction please?
Thanks
George
import java.awt.*;
import java.awt.event.*;
import javax.swing.JMenu;
import javax.swing.JLabel;
import javax.swing.JMenuItem;
import javax.swing.JButton;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
import javax.swing.ImageIcon;
import javax.swing.AbstractButton;
import javax.swing.JFrame;
import java.awt.event.KeyEvent;
import java.util.*;
public class TestCode extends JFrame {
    private static void createAndShowGUI() {
     JFrame.setDefaultLookAndFeelDecorated(true);
        JFrame frame = new JFrame("Robot Control Station");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     JMenuBar menuBar = new JMenuBar();
     JMenu fileMenu = new JMenu("Exit");
     fileMenu.setMnemonic(KeyEvent.VK_F);
     menuBar.add(fileMenu);
        JLabel emptyLabel = new JLabel("");
        emptyLabel.setPreferredSize(new Dimension(750, 750));
        frame.getContentPane().add(emptyLabel, BorderLayout.CENTER);
     JMenuItem newMenuItem = new JMenuItem("Exit Program", KeyEvent.VK_N);
     fileMenu.add(newMenuItem);
     frame.setJMenuBar(menuBar);
     frame.setVisible(true);
        //Display the window.
        frame.pack();
        frame.setVisible(true);
       //forward button
     JButton forward = new JButton("Forward");
     forward.setMnemonic(KeyEvent.VK_D);
        forward.setActionCommand("disable");
     forward.setToolTipText("Click this button to make the robot go forward.");
     forward.add(forward);
     frame.setVisible(true);
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();


thanks for the help,
i read the tutorial, and have starte dto understand how to use action listeners, but i seem to have stumbled to another problem, it seems that i dont fully undertsand how to use ActioListeners, and i cant see mto see what i'm doing wrong.
import java.awt.*;
import java.awt.event.*;
import javax.swing.JMenu;
import javax.swing.JLabel;
import javax.swing.JMenuItem;
import javax.swing.JButton;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
import javax.swing.ImageIcon;
import javax.swing.AbstractButton;
import javax.swing.JFrame;
import java.awt.event.KeyEvent;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.*;
public class TestCode extends JFrame implements WindowListener,ActionListener {
     public void actionPerformed(ActionEvent e) {
     forward = new JButton("Forward");
     frame.setLayout(null);
     forward.setMnemonic(KeyEvent.VK_D);
     forward.setActionCommand("Forward");
     forward.setToolTipText("Click this button to make the robot go forward!");
     add(forward);
     addActionListener(this);
     frame.add(forward);
     JFrame frame;
     JButton forward;
     frame.addActionListener(this);
     private static void createAndShowGUI() {
     JFrame.setDefaultLookAndFeelDecorated(true);
        JFrame frame = new JFrame("Robot Control Station");
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     frame.addWindowListener(this);
     frame.pack();
        frame.setVisible(true);
     //JMenuBar createMenuBar;
     JMenuBar menuBar = new JMenuBar();
     JMenu fileMenu = new JMenu("Exit");
     fileMenu.setMnemonic(KeyEvent.VK_F);
     menuBar.add(fileMenu);
        JLabel emptyLabel = new JLabel("");
        emptyLabel.setPreferredSize(new Dimension(750, 750));
        frame.getContentPane().add(emptyLabel, BorderLayout.CENTER);
     JMenuItem newMenuItem = new JMenuItem("Exit Program", KeyEvent.VK_N);
     fileMenu.add(newMenuItem);
     frame.setJMenuBar(menuBar);
    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
     it points me to line 22 which is frame.addActionListener(this); , it tells me that an identifier is expected, and it is an illegal start of type. I can't get my head round it. Can anyone turn me to the right direction again please?

Override abstract method ?

hi all
package jgraph;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class JFrameMain extends javax.swing.JFrame {
      public JFrameMain() {
        initComponents();
    // <editor-fold defaultstate="collapsed" desc=" Generated Code ">
    private void initComponents() {
        jPanel1 = new javax.swing.JPanel();
        jSeparator1 = new javax.swing.JSeparator();
        label = new javax.swing.JTextField();
        jMenuBar1 = new javax.swing.JMenuBar();
        menu1 = new javax.swing.JMenu();
        menu2 = new javax.swing.JMenu();
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("\u041b\u0430\u0431\u043e\u0440\u0430\u0442\u043e\u0440\u043d\u0430\u044f \u0440\u0430\u0431\u043e\u0442\u0430 \u0428\u0438\u043b\u043e\u0432");
        setBackground(new java.awt.Color(204, 204, 255));
        setCursor(new java.awt.Cursor(java.awt.Cursor.DEFAULT_CURSOR));
        jPanel1.setBackground(new java.awt.Color(204, 204, 255));
        jPanel1.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                clickHandler(evt);
            public void mouseEntered(java.awt.event.MouseEvent evt) {
                enterHandler(evt);
        jPanel1.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
            public void mouseMoved(java.awt.event.MouseEvent evt) {
                moveHandler(evt);
        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 882, Short.MAX_VALUE)
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 548, Short.MAX_VALUE)
        label.setFocusable(false);
        menu1.setText("\u0413\u0440\u0430\u0444");
        jMenuBar1.add(menu1);
        menu2.setText("About");
        jMenuBar1.add(menu2);
        setJMenuBar(jMenuBar1);
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(label, javax.swing.GroupLayout.DEFAULT_SIZE, 882, Short.MAX_VALUE)
            .addComponent(jSeparator1, javax.swing.GroupLayout.DEFAULT_SIZE, 882, Short.MAX_VALUE)
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jSeparator1, javax.swing.GroupLayout.PREFERRED_SIZE, 2, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(3, 3, 3)
                .addComponent(label, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
        pack();
    }// </editor-fold>
    private void clickHandler(java.awt.event.MouseEvent evt) {
        int nx, ny, nsize = 20;
        nx = evt.getX();
        ny = evt.getY();
        Circle c = new Circle();
        c.x = nx;
        c.y = ny;
        c.size = nsize;
        c.Draw();
        label.setText("x = " + nx + " y = " + ny + " size = " + nsize);
    private void moveHandler(java.awt.event.MouseEvent evt) {
        int mX, mY;
        mX = evt.getX();
        mY = evt.getY();
        label.setText("x = " + mX + " y = " + mY);
    private void enterHandler(java.awt.event.MouseEvent evt) {
        int mX, mY;
        mX = evt.getX();
        mY = evt.getY();
        label.setText("x = " + mX + " y = " + mY);
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new JFrameMain().setVisible(true);
    // Variables declaration - do not modify
    private javax.swing.JMenuBar jMenuBar1;
    public javax.swing.JPanel jPanel1;
    private javax.swing.JSeparator jSeparator1;
    public javax.swing.JTextField label;
    private javax.swing.JMenu menu1;
    private javax.swing.JMenu menu2;
    // End of variables declaration
abstract public class Shape{
    Color red = Color.RED;
    int x, y, size;
    abstract public void Draw();
class Circle extends Shape {
    int x, y, size = 20;
    Color red = Color.RED;
    public void Draw(Graphics g){
        g.setColor(red);
        g.drawOval(x, y, size, size);
}what problem is?
How can i draw array of Circle?
how can i Drag them?

Don't know how you're getting that. 1st of all your code asis will not compile at anyrate. Perhaps you've taken out 'real' code just for posting, don't know. But in order to get your code to compile 'asis' you need to comment out all the lines will '...' (or remove them), and get rid of your Exception throwing, since you are not doing anything to thow any. Then it compiles clean. So, you need to post your real code I guess if you want a valid answer.

Abstract Method Overriding Problem

I have an abstract class called "Employee" with an abstract method called "ReturnBasicInfo()" defined.
I have two subclasses, SalariedEmployee and HourlyEmployee, and each has their own version of ReturnBasicInfo(). The compiler is not letting me do this, however, and I have no idea why.
I keep getting this error:
SalariedEmployee.java:6: SalariedEmployee is not abstract and does not override
abstract method returnBasicInfo() in Employee.The abstract method signature is this:
public abstract String returnBasicInfo(Employee e);Any idea why this might be happening? I have another abstract method called toVector() that's overriden in the subclasses and that one works fine, so I'm stumped on this. The only difference between the two is that this method takes arguments and the other doesn't. Is that why it can't be overriden?
Thanks in advance for any help!

"...In the instructor's example code, he actually
overrode toString with this method. I thought I might
be using the real toString(), though, so that's why I
changed the name to returnBasicInfo(). I didn't end up
using toString(), though. Maybe I ought to go back to
calling it toString()..."
Yes, this SHOULD be overridden in toString(). Do go
back to it.
The "real" toString()? Do you mean the default
version in java.lang.Object, the one that just prints
out the object reference when it's called?
Hmm, I guess. I got confused because I'm swapping between String and double values a lot. Taking in an entered number as a String and converting it to a double.
I think I originally confused toString() with String.valueOf().
I wouldn't have getYearlySalary() for SalariedEmployee
and getHourlySalary() for HourlyEmployee. That
defeats the purpose of polymorphism and dynamic
typing. Yes, but I do have one polymorphic method --pay(). Each Employee is paid a different way. The one method we were supposed to be able to call on all Employees is just pay(). There is one version of pay() for HourlyEmployees that uses gethourly_rate() and gethours_worked() to get hourly rate and hours worked. The other version of pay() in SalariedEmployees takes in their yearly salary and number of pay periods worked.
Better to have a getSalary() method in your
Employee interface and let each subclass implement it
the way they want to. SalariedEmployee will return
their yearly salary, HourlyEmployee will return
hourlySalary*hoursWorkedOK, that's one idea.
But darnit, I would still like to know how to get my original design to work. So I should change returnBasicInfo() to toString(), you think?

Abstract Methods and Override Don't work For SubPackages

I have an abstract class called "A" in a package called test.
package test;
public abstract class A
    int x;
    public A (int x)
        this.x = x;
    abstract void testMethod();
}And I have a sub class of "A" called "SubA" in a sub package of "test" called "test.subPkg":
package test.subPkg;
import test.A;
public class SubA extends A {
    public SubA(int x)
        super(x);
    @Override
    void testMethod()
        throw new UnsupportedOperationException("Not supported yet.");
}Now when I try to compile, it gives me the error:
/home/eric/NetBeansProjects/drum-tabber4/trunk/src/test/subPkg/SubA.java:6: test.subPkg.SubA is not abstract and does not override abstract method testMethod() in test.A
public class SubA extends A {
/home/eric/NetBeansProjects/drum-tabber4/trunk/src/test/subPkg/SubA.java:14: method does not override or implement a method from a supertype
If I put SubA in the above package "test" instead of "test.subPkg", it compiles fine. But I don't want to do that because I have a lot of sub classes that are organized differently in separate sub packages.
If I make A an interface, it compiles fine. But I don't want to do that either because I want A to implement the constructor.
Anyone have any idea of how to fix this issue?

Now when I try to compile, it gives me the error:
/home/eric/NetBeansProjects/drum-tabber4/trunk/src/test/subPkg/SubA.java:6: test.subPkg.SubA is not abstract and does not override abstract method testMethod() in test.A
public class SubA extends A {
/home/eric/NetBeansProjects/drum-tabber4/trunk/src/test/subPkg/SubA.java:14: method does not override or implement a method from a supertype
If I put SubA in the above package "test" instead of "test.subPkg", it compiles fine. But I don't want to do that because I have a lot of sub classes that are organized differently in separate sub packages.Thats because method testMethod() in class A has a default access modifier. Meaning, that testMethod() will only be visible within the same package and not outside of package test. Expand the access modifier of testMethod() in class A, either make it protected or public, like this...
protected abstract void testMethod();
OR
public abstract void testMethod();

Should @Override apply to implementation of interface/abstract methods?

To me this is a minor but irritating incompatibility between Java 5 and 6. In 5 the @Override annotation only applied when an actual concrete method was overridden. In 6 it also applies when an interface or abstract method is implemented.
To my mind only the first case is actually overriding. Further the purpose of the @Override, AFAIKS, is to catch errors where you accidentally override a method, or write a method which you expect to override another, but get the signature wrong.
This kind of error isn't going to happen on implementing a method because you will get a real syntax error.
If we were going to use annotations to guarantee implementation it should be @Implements

sabre150 wrote:
masijade. wrote:
Having spend some time recently changing from extending abstract classes to implementing interfaces I would hate to have two different annotations!It would be annoying, yes, in that case, but it would still be more "technically" correct to have a different tag. And, if we are going to insist that "newbies" here at least attempt to adhere to standards/procedures/whatever, we should be willing to do the same. ;-)It would be more "technically" correct to have an 'override' key word in the same way as in C# . The annotation approach is used to make up for a deficiency in the language specification. If one applies the KISS principle or the 'principle of least surprise' then just having one annotation makes sense.Okay then, we agree to disagree. But getting even farther away in the "use" of the term as opposed to the "definition" of the term isn't helping to make up for the deficiency in the language.
Of course, in the practical sense it is better to have one as it is, then, least likely to "break" in a backwards compatability sense (even when it only applies to compilation and not execution).

"Abstract" method in a non-abstract class

Hi all.
I have a class "SuperClass" from which other class are extended...
I'd like to "force" some methods (method1(), method2, ...) to be implemented in the inherited classes.
I know I can accomplish this just implementing the superclass method body in order to throw an exception when it's directly called:
void method1(){
throw new UnsupportedOperationException();
}...but I was wondering if there's another (better) way...
It's like I would like to declare some abstract methods in a non-abstract class...
Any ideas?

The superclass just models the information held by
the subclasses.
The information is taken from the database, by
accessing the proper table (one for each subclass).??
What do you mean by "models the information"?
You should use inheritance (of implementation) only when the class satisfies the following criteria:
1) "Is a special kind of," not "is a role played by a";
2) Never needs to transmute to be an object in some other class;
3) Extends rather than overrides or nullifies superclass;
4) Does not subclass what is merely a utility class (useful functionality you'd like to reuse); and
5) Within PD: expresses special kinds of roles, transactions, or things.
Why are you trying to force these mystery methodsfrom the superclass?
It's not mandatory for me to do it... I 'd see it
just like a further way to check that the subclasses
implements these methods, as they have to do.That's not a good idea. If the superclass has no relation to the database, it shouldn't contain methods (abstract or otherwise) related to database transactions.
The subclasses are the classes that handle db
transaction.
They are designed as a binding to a db table.And how is the superclass designed to handle db transactions? My guess (based on your description) is that it isn't. That should tell you right away that the subclasses should not extend your superclass.

Non-abstract methods in a Abstract class

Abstract Class can contain Non-abstract methods.
and Abstract Classes are not instantiable as well
So,
What is the purpose of Non-abstract methods in a Abstract class.
since we can't create objects and use it
so these non-abstract methods are only available to subclasses.
(if the subclass is not marked as abstract)
is that the advantage that has.(availability in subclass)
??

For example, the AbstractCollection class (in
java.util) provides an implementation for many of the
methods defined in the Collection interface.
Subclasses only have to implement a few more methods
to fulfill the Collection contract. Subclasses may
also choose to override the AbstractCollection
functionality if - for example - they know how to
provide an optimized implementation based on
characteristics of the actual subclass.Another example is the abstract class MouseAdapter that implements MouseListener, MouseWheelListener, MouseMotionListener, and that you can use instead of these interfaces when you want to react to one or two types of events only.
Quoting the javadocs: "If you implement the MouseListener, MouseMotionListener interface, you have to define all of the methods in it. This abstract class defines null methods for them all, so you can only have to define methods for events you care about."

Abstract method question

Even though the method add in AbstractTest does not throw AnotherException, it compiles fine. Why is it ?
public class AbstractTest extends MyAbstract{
public void add()throws MyException {
class MyException extends Exception {
class AnotherException extends Exception {
abstract class MyAbstract {
abstract public void add() throws MyException, AnotherException;
}

JoachimSauer wrote:
When posting code, please use the code-tags (select your code and press "CODE" just above the text field). It is much easier to read this way.
A method overriding another method is perfectly free to reduce the checked exceptions that it can throw. That's because "throws Foo" only means "I could theoretically throw Foo". It doesn't guarantee that it ever actually throws Foo.
It must not add new ones, however.I like to look at it this way: "throws X" does not mean "I promise to throw X." On the contrary, it means, "I promise +not+ to throw anything +other than+ X (or its subclasses)." So when I child class "narrows" that throws clause it just means that it promises not to throws anything outside of an even smaller subset.

Override Abstract Methods in NetBeans 6.1

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