Losing my mind with a scrollpane

Question

Hello all. I am trying to get a scroll pane to work in an application that I have built for school. I am trying to get an amortization table to scroll through for a mortgage calculator. It isn't recognizing my scrollpane and I am not sure why. Could someone give me a push in the right direction.
import javax.swing.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.text.*;
public class MortCalcWeek3 extends JFrame implements ActionListener
     DecimalFormat twoPlaces = new DecimalFormat("#,###.00");//number format
     int L[] = {7, 15, 30};
     double I[] = {5.35, 5.5, 5.75};
     double P, M, J, H, C, Q;
     JPanel panel = new JPanel ();//creates the panel for the GUI
     JLabel title = new JLabel("Mortgage Calculator");
     JLabel PLabel = new JLabel("Enter the mortgage amount: ");
     JTextField PField = new JTextField(10);//field for obtaining user input for mortgage amount
     JLabel choices = new JLabel ("Choose the APR and Term in Years");
     JTextField choicestxt = new JTextField (0);
     JButton calcButton = new JButton("Calculate");
     JTextField payment = new JTextField(10);
     JLabel ILabel = new JLabel("Annual Percentage Rate: choose one");
     String [] IChoice = {I[0] + "", I[1] + "", I[2] + ""};
     JComboBox IBox = new JComboBox(IChoice);
     JLabel LLabel = new JLabel("Term (in years): choose one");
     String [] LChoice = {L[0] + "", L[1] + "", L[2] + ""};
     JComboBox LBox = new JComboBox(LChoice);
     JLabel amortBox = new JLabel("Amortiaztion Table");
     JScrollPane amortScroll = new JScrollPane();
     public MortCalcWeek3 () //creates the GUI window
                    super("Mortgage Calculator");
                    setSize(300, 400);
                    panel.setBackground (Color.white);
                    panel.setLayout(null);
                    panel.setPreferredSize(new Dimension(500, 500));
                    setResizable(false) ;
                    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    //Creates the container
                    Container contentPane = getContentPane();
                    FlowLayout fresh = new FlowLayout(FlowLayout.LEFT);
                    panel.setLayout(fresh);
                    //identifies trigger events
                    calcButton.addActionListener(this);
                    PField.addActionListener(this);
                    IBox.addActionListener(this);
                    LBox.addActionListener(this);
                    panel.add(PLabel);
                    panel.add(PField);
                    panel.add(choices);
                    panel.add(choicestxt);
                    panel.add(ILabel);
                    panel.add(IBox);
                    IBox.setBackground (Color.white);
                    panel.add(LLabel);
                    panel.add(LBox);
                    LBox.setBackground (Color.white);
                    panel.add(calcButton);
                    calcButton.setBackground (Color.white);
                    panel.add(payment);
                    payment.setBackground (Color.white);
                    panel.add(amortBox);
                    payment.setEditable(false);
                    panel.add(amortScroll);
                    setContentPane(panel);
                    setVisible(true);
     }// end of GUI info
          public void actionPerformed(ActionEvent e) {
               MortCalcWeek3();     //calls the calculations
          public void MortCalcWeek3() {     //performs the calculations from user input
               double P = Double.parseDouble(PField.getText());
               double I = Double.parseDouble((String) IBox.getSelectedItem());
               double L = Double.parseDouble((String) LBox.getSelectedItem());
               double J = (I  / (12 * 100));//monthly interest rate
               double N = (L * 12);//term in months
               double M = (P * J) / (1 - Math.pow(1 + J, - N));//Monthly Payment
             String showPayment = twoPlaces.format(M);
             payment.setText(showPayment);
     //public void amort() {
               //int N = (L * 12);
               int month = 1;
                         while (month <= N)
                              //performs the calculations for the amortization
                              double H = P * J;//current monthly interest
                              double C = M - H;//monthly payment minus monthly interest
                              double Q = P - C;//new balance
                              P = Q;//sets loop
                              month++;
                              String showAmort = twoPlaces.format(H + C + Q);
                            amortScroll(showAmort);
          public static void main(String[] args) {
          MortCalcWeek3 app = new MortCalcWeek3();
}//end main
}//end the programI am getting an error stating that it cannot resolve the symbol and it is reffering to my "amortScroll(showAmort);" statement. Please help.

Answer 1

a scrollpane generally contains another component e.g. in this a JTextArea,
where you can display the output of your while().
try these changes
1)
JLabel amortBox = new JLabel("Amortiaztion Table");
JTextArea ta = new JTextArea();//<----------------------added
//JScrollPane amortScroll = new JScrollPane();//<-------changed to below line
JScrollPane amortScroll = new JScrollPane(ta);
2)
panel.add(amortScroll);
amortScroll.setPreferredSize(new Dimension(275,100));//<----------added
setContentPane(panel);
setVisible(true);
3)
String showAmort = twoPlaces.format(H + C + Q);
//amortScroll(showAmort);//<---------------changed to below line
ta.append(showAmort+"\n");