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Java inserts backspace into uneditable JTextArea

I have a JTextArea that cannot be selected in a specific setting. However, in this parameter, the user can still use the space bar and return key. To place the space, I have the following code,

if (e.getKeyChar() == KeyEvent.VK_SPACE) {
    editor.insert(" ", editor.getCaretPosition());
}

I have a problem with backspace. I tried this

if (e.getKeyChar() == KeyEvent.VK_BACK_SPACE) {
    editor.insert("\b", editor.getCaretPosition());
}

It seems like a little space is added when backspace is pressed. It is not as much as space, and it is almost imperceptible when pressed once. However, this is definitely not reverse space. In the worst case, I will have to copy all the characters to the carriage position - 1 and add them to all the characters after the carriage position, but I do not like this solution.

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import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;

import javax.swing.*;
import javax.swing.text.BadLocationException;
import javax.swing.text.PlainDocument;

@SuppressWarnings("serial")
public class TextAreaFun extends JPanel {
   public static final String SPACE = "space";
   public static final String BACK_SPACE = "back space";
   private JTextArea textArea = new JTextArea(15, 50);

   public TextAreaFun() {
      // create our key bindings
      // only allow key presses to initiate an action if the JTextArea has focus
      int condition = JComponent.WHEN_FOCUSED;
      InputMap taInputMap = textArea.getInputMap(condition);
      ActionMap taActionMap = textArea.getActionMap();

      taInputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0), SPACE);
      taInputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_BACK_SPACE, 0),
            BACK_SPACE);
      taActionMap.put(SPACE, new KeyAction(textArea, SPACE));
      taActionMap.put(BACK_SPACE, new KeyAction(textArea, BACK_SPACE));

      // checkbox that stops all editing except for that specified in the 
      // key bindings above
      JCheckBox chkBox = new JCheckBox(new AbstractAction("Prevent Editing") {
         {
            putValue(SELECTED_KEY, Boolean.FALSE); // default to unchecked
            putValue(MNEMONIC_KEY, KeyEvent.VK_P);
         }

         @Override
         public void actionPerformed(ActionEvent evt) {
            boolean selection = (Boolean) getValue(SELECTED_KEY);
            textArea.setEditable(!selection);
         }
      });
      JPanel bottomPanel = new JPanel();
      bottomPanel.add(chkBox);

      setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
      add(new JScrollPane(textArea));
      add(Box.createVerticalStrut(10));
      add(bottomPanel);
   }

   private static void createAndShowGui() {
      TextAreaFun mainPanel = new TextAreaFun();

      JFrame frame = new JFrame("TextAreaFun");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

@SuppressWarnings("serial")
// action to be initiated by key bindings
class KeyAction extends AbstractAction {
   private PlainDocument textAreaDocument;
   private String title;

   public KeyAction(JTextArea textArea, String title) {
      this.textAreaDocument = (PlainDocument) textArea.getDocument();
      this.title = title;
   }

   @Override
   public void actionPerformed(ActionEvent e) {
      if (title.equals(TextAreaFun.SPACE)) {
         try {
            textAreaDocument.insertString(textAreaDocument.getLength(), " ",
                  null);
         } catch (BadLocationException e1) {
            e1.printStackTrace();
         }
      } else if (title.equals(TextAreaFun.BACK_SPACE)) {
         if (textAreaDocument.getLength() == 0) {
            return;
         }
         try {
            textAreaDocument.remove(textAreaDocument.getLength() - 1, 1);
         } catch (BadLocationException e1) {
            e1.printStackTrace();
         }
      }
   }
}
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