IMC calculatrice graphique de Java;

J'ai voulu créer un IMC calculatrice en utilisant l'interface graphique en Java. Je suis très nouveau à l'interface utilisateur et même Java. La calculatrice est supposer pour l'affichage de l'IMC avec des conseils et même l'heure et la date. Toutefois, seul l'IMC est de s'afficher pendant que le reste ne peut pas.. j'ai été à la recherche en ligne sur la façon d'afficher les résultats à partir de si la condition else en ligne, mais en vain. C'est mon code;

public class BMI extends JFrame implements ActionListener {
private static final JButton JButton = null;
private JFrame frame;
private JPanel panel;
private JLabel heightLabel, weightLabel, BMILabel;
private JTextField height, weight, result;
private JButton calculate;
String Height, Weight;
double number1, number2, BMI;
static String output = "Results";
static int jopIcon = JOptionPane.QUESTION_MESSAGE;
boolean bFlag = true; //state, true means no exception
public BMI() {
frame = new JFrame("BMI Calculator");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//create labels for the height and weight textfields 
heightLabel = new JLabel("Your height in meters:");
weightLabel = new JLabel("Your weight in kilograms: ");
//create a "this is your BMI" label
BMILabel = new JLabel("Your BMI is ");
//create a result label to hold the BMI value
result = new JTextField("");
//create a JTextField to hold the person's height in kilograms
height = new JTextField(1);
//create a JTextField to hold the person's weight in metres
weight = new JTextField(1);
calculate = new JButton("Calculate BMI");
//set up the JPanel to go on the JFrame 
panel = new JPanel();
panel.add(heightLabel);
panel.add(height);
//add the weight label and weight textfield to the panel
panel.add(weightLabel);
panel.add(weight);
//add the button to the panel
panel.add(BMILabel);
//add the label that holds the result to the panel
panel.add(result);
//add the panel to the frame 
panel.add(calculate);
//add the BMI label to the panel
frame.getContentPane().add(panel);
JPanel p1 = new JPanel();
panel.setLayout(new GridLayout(4, 1));
add(p1, BorderLayout.SOUTH);
calculate.addActionListener(this);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
frame.setVisible(true);//important must HAVE@! if not GUI will not be display
}
public String getDateTime() {
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date date = new Date();
return dateFormat.format(date);
}
public void calculateBMI(double number1, double number2) {
try {
BMI = number2 / ((number1) * 2);
} catch (NumberFormatException nfe) {
output += "\n\n Whoa! Input error: must enter valid integers";//if exception comes    out, prepare error message
jopIcon = JOptionPane.ERROR_MESSAGE;
}
}
public void calculate() {
Height = height.getText();
Weight = weight.getText();//declare the Height string with Jtext height
try {
number1 = Double.parseDouble(Height);
number2 = Double.parseDouble(Weight);//exception may come out
calculateBMI(number1, number2);
} finally {
if (BMI >= 27.5) {
output += "\n\n You're in the High Risk zone(UnHealthy). Please start losing weight! It's a MUST!";
} else if (BMI <= 23 || BMI < 27.4) {
output += "\n\n You're in the Moderate Risk zone. Please start going on diet and lose some weight";
} else if (BMI <= 18.5 || BMI < 22.9) {
output += " You're in the Low Risk zone(Healthy). Hopefully you can maintain this way! ^^";
} else if (BMI < 18.4) {
output += "\n\n You really need to start eating more. Too skinny and unhealthy for your body";
}
}
}
public static void main(String[] args) {
BMI bmi = new BMI();
}
@Override
public void actionPerformed(ActionEvent e) {
//call the calculate
this.calculate();
result.setText("" + BMI);
//TODO Auto-generated method stub
}
}