Fibbonaci GUI calcualtor

Problem:

See the output

Output:

Solution:

//********************FibonacciNumbersApp.java*********/
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class FibonacciNumbersApp extends JFrame {

 private JLabel inputLabel, resultLabel;
 private JTextField InputTextField;
 private JButton goButton;
 private int number;
 private JPanel northPanel, southPanel;
 private FibonacciWorker worker;
 public  FibonacciNumbersApp() {
  
  northPanel = createNorthPanel();
  southPanel = createSouthPanel();
 
  Container contentPane = getContentPane();
  contentPane.setLayout(new GridLayout(2,1));
  contentPane.add(northPanel);
  contentPane.add(southPanel);
 }
 
 private JPanel createNorthPanel() {
  JPanel panel = new JPanel();
  
  inputLabel = new JLabel("Get The Fibonnaci of: ");
  InputTextField = new JTextField(6);
  
  panel.add(inputLabel);
  panel.add(InputTextField);
  
  return panel;
 }
 
 private JPanel createSouthPanel() {
  JPanel panel = new JPanel();
  
  goButton = new JButton("Go");
  goButton.addActionListener(new ActionListener() {
   @Override
   public void actionPerformed(ActionEvent e) {
    try {
     number = Integer.parseInt(InputTextField.getText());
    } catch (NumberFormatException e1) {
     resultLabel.setText("Input must be numeric!");
     return;
    }
    worker = new FibonacciWorker(number, resultLabel);
    worker.execute();
    resultLabel.setText("Calculating..");
   }
  });
  resultLabel = new JLabel("Ouptut will appear here: ");
  
  panel.add(goButton);
  panel.add(resultLabel);
  return panel;
 }

 
 
 public static void main(String[] args) {
  FibonacciNumbersApp demo = new FibonacciNumbersApp();
  demo.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  
  demo.setSize(350, 150);
  demo.setVisible(true);
  demo.setResizable(false);
  demo.setLocationRelativeTo(null);
  
 }
 
}
//********************FibonacciWorker.java*********/
import java.util.concurrent.ExecutionException;
import javax.swing.JLabel;
import javax.swing.SwingWorker;

public class FibonacciWorker extends SwingWorker<Long, Object> {

 private int number;
 private JLabel resultLabel;
 
 
 public FibonacciWorker(int number, JLabel resultLabel) {
  this.number = number;
  this.resultLabel = resultLabel;
  
 }
 
 
 @Override
 protected java.lang.Long doInBackground() throws Exception {
 
  return fibonacci(number);
 }
 
 @Override
 protected void done() {
  try {
   resultLabel.setText(get().toString());
  } catch (InterruptedException e) {
   resultLabel.setText("Interupted while waiting for result");
  } catch (ExecutionException e) {
   resultLabel.setText("Error encountred during execution");
  }
 
 }
 
 public  long fibonacci(int n) {
  if(n==0 || n==1) 
   return n;
  else 
   return fibonacci(n-1) + fibonacci(n-2);
 }
 
 
}