java - Selecting Password row and Pasting in notepad reveals the password

Question

I have been facing the above mentioned problem in my java application that I recently created. Even though I clearly set the field as JPasswordField and have tried to mask the password with astericks, I continue to face this issue. I issue does not occur when we edit the password field it occurs only when you select the row. For example I have 2 columns in a row and if I select the entire row and try to copy paste the row in notepad the pasword appears. I'm new in the world of java programming, if someone can help will be of great help.

Answer 1

What you want is rather logical. When copy-pasting the data from your table the rendering should be respected.

The standard copy action will use the data available in your model, where the password is available as plain text. We could start a discussion whether you want to have your model contain a password as plain text, without any hashing applied to it ... but that does not answer your question.

For your question you should modify the behavior of the cut/copy actions of the JTable. Take a look at the Drag and drop Swing tutorial, and more specifically to the Adding Cut, Copy and Paste section. Unfortunately I do not immediately find an example to refer to.

Edit

Find below an example of a JXTable which uses the rendered values for the copy-action (I did not copy-pasted the imports). A little side-note about the code:

1. It uses SwingX to illustrate something for kleopatra as well
2. The example TableModel and its elements are rather stupid. To avoid too much work I needed something similar to our real product to be able to copy some of the code
3. The SpeedStringValue and AltitudeStringValue classes violate the StringValue interface as they return null. I was too lazy to define a new interface, and the StringValue instance I set on the SwingX DefaultTableRenderer behaves according to the documentation. I think however that having separate StringValue instances which each have knowledge for converting a specific class to String is a real-world use-case which is lacking in SwingX
4. The TransferHandler reuses the StringValue logic to create a Table containing only String instances, and then falls back on the default JTable behavior. This allows to reuse the logic implemented in the renderer, and allows to copy the visual values instead of the model values. I am not sure whether this is the nicest solution, but it works. It would be nice however if similar behavior was standard in SwingX, as they already have the infrastructure

5. The code lacks comments as it was already long enough. If something is unclear, leave a comment and I will try to clarify

   public class TableTransferHandlerDemo {
   
     public static void main( String[] args ) throws InvocationTargetException, InterruptedException {
       EventQueue.invokeAndWait( new Runnable() {
         public void run() {
           JFrame frame = new JFrame( "TestFrame" );
   
           JPanel contentPane = new JPanel( new BorderLayout(  ) );
           contentPane.add( createTable(), BorderLayout.CENTER );
           frame.getContentPane().add( contentPane );
   
           frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
           frame.pack();
           frame.setVisible( true );
         }
       } );
     }
   
     private static CompositeStringValue createStringValue() {
       CompositeStringValue stringValue = new CompositeStringValue();
       stringValue.delegates.add( new AltitudeStringValue() );
       stringValue.delegates.add( new SpeedStringValue() );
       return stringValue;
     }
   
     public static JXTable createTable(){
       final JXTable table = new JXTable(  );
       table.setSelectionMode( ListSelectionModel.MULTIPLE_INTERVAL_SELECTION );
       table.setModel( createTableModel() );
       CompositeStringValue stringValue = createStringValue();
       table.setDefaultRenderer( Object.class, new DefaultTableRenderer( stringValue ) );
       table.setTransferHandler( new TableTransferHandler( table, stringValue ) );
       //make sure ctrl-c triggers a copy
       InputMap inputMap = table.getInputMap( JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT );
       inputMap.put( KeyStroke.getKeyStroke( KeyEvent.VK_C, InputEvent.CTRL_MASK ), "copyAction" );
       table.getActionMap().put( "copyAction", new AbstractAction() {
         public void actionPerformed( ActionEvent e ) {
           ActionEvent event = new ActionEvent( table, e.getID(), e.getActionCommand(), e.getWhen(), e.getModifiers() );
           TransferHandler.getCopyAction().actionPerformed( event );
         }
       } );
       return table;
     }
   
     public static class Speed{
       public double speed;
       public String unit = "km/h";
       public Speed( double speed ){ this.speed = speed;}
     }
     public static class Altitude{
       public double altitude;
       public String unit = "m";
       public Altitude( double altitude ){ this.altitude = altitude; }
     }
     public static class SpeedStringValue implements StringValue{
       public String getString( Object o ) {
         if ( o instanceof Speed ){
           return ( ( Speed ) o ).speed + ( ( Speed ) o ).unit;
         }
         return null;
       }
     }
     public static class AltitudeStringValue implements StringValue{
       public String getString( Object o ) {
         if ( o instanceof Altitude ){
           return ( ( Altitude ) o ).altitude + ( ( Altitude ) o ).unit;
         }
         return null;
       }
     }
     public static class CompositeStringValue implements StringValue{
       public List<StringValue> delegates = new ArrayList<StringValue>(  );
       public String getString( Object o ) {
         for ( StringValue stringValue : delegates ) {
           String string = stringValue.getString( o );
           if ( string != null ) return string;
         }
         return o != null ? o.toString() : "null";
       }
     }
     public static TableModel createTableModel(){
       return new DefaultTableModel(
           new Object[][]{ new Object[]{ new Speed( 10 ), new Altitude( 100 )},
               new Object[]{ new Speed( 20 ), new Altitude( 200 ) }},
           new Object[]{"Speed", "Altitude"} );
     }
     public static class TableTransferHandler extends TransferHandler{
       private JXTable table;
       private StringValue stringValue;
   
       public TableTransferHandler( JXTable aTable, StringValue aStringValue ) {
         table = aTable;
         stringValue = aStringValue;
       }
       @Override
       public void exportToClipboard( JComponent aComponent, Clipboard aClipboard, int aAction ) throws IllegalStateException {
         JTable table = createTable();
         table.getTransferHandler().exportToClipboard( table, aClipboard, aAction );
       }
       @Override
       public void exportAsDrag( JComponent aComponent, InputEvent aEvent, int aAction ) {
         JTable table = createTable();
         table.getTransferHandler().exportAsDrag( table, aEvent, aAction );
       }
       @Override
       protected Transferable createTransferable( JComponent c ) {
         //this transfer handler should not create any transferables
         return null;
       }
       /**
        * Create a table, representing the JXTable containing only Strings
        */
       private JTable createTable() {
         JTable table = new JTable( new StringTableModel( this.table, stringValue ) );
         table.setSelectionModel( this.table.getSelectionModel() );//make sure the selection is synced
         return table;
       }
     }
   
     private static class StringTableModel extends AbstractTableModel {
       private JXTable delegateTable;
       private StringValue stringValue;
   
       private StringTableModel( JXTable aTable, StringValue aStringValue ) {
         delegateTable = aTable;
         stringValue = aStringValue;
       }
   
       public int getRowCount() {
         return delegateTable.getModel().getRowCount();
       }
   
       public int getColumnCount() {
         return delegateTable.getModel().getColumnCount();
       }
   
       public Object getValueAt( int aRowIndex, int aColumnIndex ) {
         return stringValue.getString( delegateTable.getValueAt( aRowIndex, aColumnIndex ) );
       }
     }
   }