Instance not storing in array. What do I have wrong here?

Instance not storing in array. What do I have wrong here?

I am having issues trying to get this program to run, the applet loads,
but when I enter a number and click ok, nothing seems to happen... I am
not sure if I have an issue with the array or where my issue might lie.
I can't seem to figure out what exactly I am doing wrong.
import java.awt.*;
import java.applet.*;
import java.awt.event.*;
import javax.swing.JOptionPane;
public class LargestApplet extends Applet implements ActionListener {
private static final long serialVersionUID = 1L;
int number =0;
double highNumber=-1;
double lowNumber=-1;
// Create components for applet
Label numberLabel = new Label("Enter a number:");
TextField numberField = new TextField(5);
Button okButton = new Button("OK");
Button cancelButton = new Button("Cancel");
Label highNumberOutputLabel = new Label("The Highest number is: 0
");
public void init() {
add(numberLabel);
add(numberField);
numberField.requestFocus();
add(okButton);
add(cancelButton);
add(highNumberOutputLabel);
setSize(400, 500); // Sets the size of the applet window
}
public void actionPerformed(ActionEvent e) {
int number = 0, highNumber = -1;
if (numberField.getText().length() == 0) {
numberField.requestFocus();
JOptionPane.showMessageDialog(null,
"Number Cannot blank", "D A T A E R R O R",
JOptionPane.ERROR_MESSAGE);
return;
}
try {
number = Integer.parseInt(numberField.getText());
} catch (NumberFormatException ex) {
numberField.requestFocus();
JOptionPane.showMessageDialog(null, "Number is invalid",
"D A T A E R R O R", JOptionPane.ERROR_MESSAGE);
return;
}
if (number < 0 || number > 10) {
numberField.requestFocus();
JOptionPane.showMessageDialog(null,
"Number must be between 0 and 10",
"D A T A E R R O R", JOptionPane.ERROR_MESSAGE);
return;
}
// Determine highest number
Integer [] numberAr = {number};
for(int i = 0; i < numberAr.length; i++)
{
number += numberAr[i];
if (numberAr[i] < lowNumber)
lowNumber = numberAr[i];
else if (numberAr[i] > highNumber)
highNumber = numberAr[i];
}
// Display the results
highNumberOutputLabel.setText("The Highest Number is: "
+ (highNumber));
}
}