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import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.event.UndoableEditEvent;
import javax.swing.event.UndoableEditListener;
import javax.swing.text.Document;
import javax.swing.text.JTextComponent;
import javax.swing.undo.CannotUndoException;
import javax.swing.undo.UndoManager;
public class Main {
public static void main(String[] argv) {
JTextComponent textcomp = new JTextArea();
final UndoManager undo = new UndoManager();
Document doc = textcomp.getDocument();
doc.addUndoableEditListener(new UndoableEditListener() {
public void undoableEditHappened(UndoableEditEvent evt) {
undo.addEdit(evt.getEdit());
}
});
textcomp.getActionMap().put("Undo", new AbstractAction("Undo") {
public void actionPerformed(ActionEvent evt) {
try {
if (undo.canUndo()) {
undo.undo();
}
} catch (CannotUndoException e) {
}
}
});
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new JScrollPane(textcomp));
frame.setSize(380, 320);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
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