Having Undo/Redo Problems

Question

Could somebody throw some light on this particular code. It's throwing up some strange errors, ie: class or interface expected, that kind of thing. so it's probably just a mattter of having the parts in the right areas
jTextArea1 jtxt = new jTextArea1();
final UndoManager undo = new UndoManager();
        Document doc = textarea.getDocument();
        doc.addUndoableEditListener(new UndoableEditListener() {
         public void undoableEditHappened(UndoableEditEvent evt) {
             undo.addEdit(evt.getEdit());
     // Create an undo action and add it to the text component
     textcomp.getActionMap().put("Undo",
         new AbstractAction("Undo") {
             public void jButton18_actionPerformed(ActionEvent evt) {
                 try {
                     if (undo.canUndo()) {
                         undo.undo();
                 } catch (CannotUndoException e) {
     // Create a redo action and add it to the text component
     textarea.getActionMap().put("Redo",
         new AbstractAction("Redo") {
             public void jButton19_actionPerformed(ActionEvent evt) {
                 try {
                     if (undo.canRedo()) {
                         undo.redo();
                 } catch (CannotRedoException e) {
         });*/

Answer 1

To create a concrete subclass of AbstractAction, you have to define a method with the signature   public void actionPerformed(ActionEvent evt)Your undo and redo actions fail to do that.