Why is my JTextArea not updating?

Question

I have code as follows:

class SimplifiedClass extends JApplet {

    private JTextArea outputText;
    // Lots of methods
    public void DoEverything() {
          


        

Answer 1

private JTextArea outputText = new JTextArea();

public void DoEverything() {
    String output = "";
    for(int i = 0; i <= 10; i++) {
        output += TaskObject.someLongTask(i);
        appendNewText(output);
    }
}

public void appendNewText(String txt) {
  SwingUtilities.invokeLater(new Runnable() {
     public void run() {
        outputText.setText(outputText.getText + txt);
       //outputText.setText(outputText.getText + "\n"+ txt); Windows LineSeparator
     }
  });
}