JTextArea w/Scroll bar wont scroll AND code drops through if statements

Question

Hi, I'm still having trouble with the text area in the following code. When you run the code, you get the top arrow on the scroll bar, but the bottom is cut off. Also, a big problem is that no matter what choice is selected from the combo box, the code drops through to the last available value each time. Someone on the forums suggested using an array list for the values in the combo box, but I have not been able to figure out how to do that. A quick example would be apprciated.
Thank you in advance for any help
//Import required libraries
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.io.*;
import java.text.*;
import java.math.*;
import java.util.*;
//Create the class
public class Week3Assignment407B extends JFrame implements ActionListener
     //Panels used in container
     private JPanel jPanelRateAndTermSelection;         
     //Variables for Menu items
     private JMenuBar menuBar;    
     private JMenuItem exitMenuItem; 
     private JMenu fileMenu; 
     //Variables for user instruction and Entry       
     private JLabel jLabelPrincipal;   
     private JPanel jPanelEnterPrincipal;  
     private JLabel jLabelChooseRateAndTerm; 
     private JTextField jTextFieldMortgageAmt;
     //Variables for combo box and buttons
     private JComboBox TermAndRate;
     private JButton buttonCompute;
     private JButton buttonNew; 
     private JButton buttonClose;
     //Variables display output
     private JPanel jPanelPaymentOutput;
     private JLabel jLabelPaymentOutput;
     private JPanel jPanelErrorOutput;
     private JLabel jLabelErrorOutput;  
     private JPanel jPanelAmoritizationSchedule;
     private JTextArea jTextAreaAmoritization;
     // Constructor 
     public Week3Assignment407B() {            
          super("Mortgage Application");      
           initComponents();      
     // create a method that will initialize the main frame for the GUI
      private void initComponents()
          setSize(700,400);
          setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);      
          Container pane = getContentPane();
          GridLayout grid = new GridLayout(15, 1);
          pane.setLayout(grid);       
          //declare all of the panels that will go inside the main frame
          // Set up the menu Bar
          menuBar = new JMenuBar();
          fileMenu = new JMenu();
          fileMenu.setText("File");        
          exitMenuItem = new JMenuItem(); 
           exitMenuItem.setText("Exit");
          fileMenu.add(exitMenuItem); 
          menuBar.add(fileMenu);       
          pane.add(menuBar);
          //*******************TOP PANEL ENTER PRINCIPAL*****************************//
          // Create a label that will advise user to enter a principle amount
          jPanelEnterPrincipal = new JPanel(); 
          jLabelPrincipal = new JLabel("Amt to borrow in whole numbers");
          jTextFieldMortgageAmt = new JTextField(10);
          GridLayout Principal = new GridLayout(1,2);
          jPanelEnterPrincipal.setLayout(Principal); 
            jPanelEnterPrincipal.add(jLabelPrincipal);
          jPanelEnterPrincipal.add(jTextFieldMortgageAmt);
          pane.add(jPanelEnterPrincipal);
          //****************MIDDLE PANEL CHOOSE INTEREST RATE AND TERM*****************//
          // Create a label that will advise user to choose an Int rate and term combination
          // from the combo box
          jPanelRateAndTermSelection = new JPanel();
          jLabelChooseRateAndTerm = new JLabel("Choose the Rate and Term");
          buttonCompute = new JButton("Compute Mortgage");
          buttonNew = new JButton("New Mortgage");
          buttonClose = new JButton("Close");
          GridLayout RateAndTerm = new GridLayout(1,5);
          //FlowLayout RateAndTerm = new FlowLayout(FlowLayout.LEFT);
          jPanelRateAndTermSelection.setLayout(RateAndTerm);
          jPanelRateAndTermSelection.add(jLabelChooseRateAndTerm);
          TermAndRate = new JComboBox();
          jPanelRateAndTermSelection.add(TermAndRate);
          TermAndRate.addItem("7 years at 5.35%");
          TermAndRate.addItem("15 years at 5.5%");
          TermAndRate.addItem("30 years at 5.75%");
          jPanelRateAndTermSelection.add(buttonCompute);
          jPanelRateAndTermSelection.add(buttonNew);
          jPanelRateAndTermSelection.add(buttonClose);
          pane.add(jPanelRateAndTermSelection);
          //**************BOTTOM PANEL TEXT AREA FOR AMORITIZATION SCHEDULE***************//
          jPanelAmoritizationSchedule = new JPanel();
          jTextAreaAmoritization = new JTextArea(26,50);
          // add scroll pane to output text area
               JScrollPane scrollBar = new JScrollPane(jTextAreaAmoritization, 
               JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                 JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
          jPanelAmoritizationSchedule.add(scrollBar);
            pane.add(jPanelAmoritizationSchedule);
          //***************ADD THE ACTION LISTENERS TO THE GUI COMPONENTS*****************//
          // Add ActionListener to the buttons and menu item
          exitMenuItem.addActionListener(this);
          buttonCompute.addActionListener(this);         
          buttonNew.addActionListener(this);
          buttonClose.addActionListener(this);
          TermAndRate.addActionListener(this);
          jTextFieldMortgageAmt.addActionListener(this);
          //*************** Set up the Error output area*****************//
          jPanelErrorOutput = new JPanel();
          jLabelErrorOutput = new JLabel();
          FlowLayout error = new FlowLayout();
          jPanelErrorOutput.setLayout(error);
          pane.add(jLabelErrorOutput);
          setContentPane(pane);
          pack();
          setVisible(true);
     //Display error messages
     private void OutputError(String ErrorMsg){
          jLabelErrorOutput.setText(ErrorMsg);
          jPanelErrorOutput.setVisible(true);
     //create a method that will clear all fields when the New Mortgage button is chosen
     private void clearFields()
          jTextAreaAmoritization.setText("");
          jTextFieldMortgageAmt.setText("");
     //**************CREATE THE CLASS THAT ACTUALLY DOES SOMETHING WITH THE EVENT*****//
     //This is the section that receives the action source and directs what to do with it
     public void actionPerformed(ActionEvent e)
          Object source = e.getSource();
          String ErrorMsg;
          double principal;
          double IntRate;
          int Term;
          double monthlypymt;
          double TermInYears = 0 ;
          if(source == buttonClose)
               System.exit(0);
          if (source == exitMenuItem) {      
                   System.exit(0);
          if (source == buttonNew)
               clearFields();
          if (source == buttonCompute)
               //Make sure the user entered valid numbers
               try
                    principal = Double.parseDouble(jTextFieldMortgageAmt.getText());
               catch(NumberFormatException nfe)
                    ErrorMsg = (" You Entered an invalid Mortgage amount"
                              + " Please try again. Please do not use commas or decimals");
                    jTextAreaAmoritization.setText(ErrorMsg);
               principal = Double.parseDouble(jTextFieldMortgageAmt.getText());
                if (TermAndRate.getSelectedItem() == "7 years at 5.35%") ;
                    Term = 7;
                    IntRate = 5.35;
                if (TermAndRate.getSelectedItem()  == "15 years at 5.5%") ;
                    Term = 15;
                    IntRate = 5.5;
                if (TermAndRate.getSelectedItem() == "30 years at 5.75%") ;
                    Term = 30;
                    IntRate = 5.75;
               //Variables have been checked for valid input, now calculate the monthly payment
               NumberFormat formatter = new DecimalFormat ("$###,###.00");
               double intdecimal = intdecimal = IntRate/(12 * 100);
               int months = Term * 12;
               double monthlypayment = principal *(intdecimal / (1- Math.pow((1 + intdecimal),-months)));
               //Display the Amoritization schedule
               jTextAreaAmoritization.setText(" Loan amount of " + formatter.format(principal)
                                                + "\n"
                                                + " Interest Rate is " +  IntRate + "%"
                                        + "\n"
                                        + " Term in Years "  + Term
                                        + " Monthly payment "+  formatter.format(monthlypayment)
                                        + "\n"
                                        + "  Amoritization is as follows:  "
                                        + "------------------------------------------------------------------------");
     public Insets getInsets()
          Insets around = new Insets(35,20,20,35);
          return around;
     //Main program     
     public static void main(String[]args) { 
          Week3Assignment407B frame = new Week3Assignment407B(); 
   }

Answer 1

here's your initComponents with a couple of changes, the problem was the Gridlayout(15,1)
also, the scrollpane needed a setPreferredSize()
  private void initComponents()
    setSize(700,400);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    //Container pane = getContentPane();
    JPanel pane = new JPanel();
    //GridLayout grid = new GridLayout(15, 1);
    GridLayout grid = new GridLayout(2, 1);
    pane.setLayout(grid);
    menuBar = new JMenuBar();
    fileMenu = new JMenu();
    fileMenu.setText("File");
    exitMenuItem = new JMenuItem();
    exitMenuItem.setText("Exit");
    fileMenu.add(exitMenuItem);
    menuBar.add(fileMenu);
    //pane.add(menuBar);
    setJMenuBar(menuBar);
    jPanelEnterPrincipal = new JPanel();
    jLabelPrincipal = new JLabel("Amt to borrow in whole numbers");
    jTextFieldMortgageAmt = new JTextField(10);
    GridLayout Principal = new GridLayout(1,2);
    jPanelEnterPrincipal.setLayout(Principal);
      jPanelEnterPrincipal.add(jLabelPrincipal);
    jPanelEnterPrincipal.add(jTextFieldMortgageAmt);
    pane.add(jPanelEnterPrincipal);
    jPanelRateAndTermSelection = new JPanel();
    jLabelChooseRateAndTerm = new JLabel("Choose the Rate and Term");
    buttonCompute = new JButton("Compute Mortgage");
    buttonNew = new JButton("New Mortgage");
    buttonClose = new JButton("Close");
    GridLayout RateAndTerm = new GridLayout(1,5);
    jPanelRateAndTermSelection.setLayout(RateAndTerm);
    jPanelRateAndTermSelection.add(jLabelChooseRateAndTerm);
    TermAndRate = new JComboBox();
    jPanelRateAndTermSelection.add(TermAndRate);
    TermAndRate.addItem("7 years at 5.35%");
    TermAndRate.addItem("15 years at 5.5%");
    TermAndRate.addItem("30 years at 5.75%");
    jPanelRateAndTermSelection.add(buttonCompute);
    jPanelRateAndTermSelection.add(buttonNew);
    jPanelRateAndTermSelection.add(buttonClose);
    pane.add(jPanelRateAndTermSelection);
    jPanelAmoritizationSchedule = new JPanel();
    jTextAreaAmoritization = new JTextArea(26,50);
    JScrollPane scrollBar = new JScrollPane(jTextAreaAmoritization,
      JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
    scrollBar.setPreferredSize(new Dimension(500,100));//<------------------------
    jPanelAmoritizationSchedule.add(scrollBar);
    getContentPane().add(pane,BorderLayout.NORTH);
    getContentPane().add(jPanelAmoritizationSchedule,BorderLayout.CENTER);
    exitMenuItem.addActionListener(this);
    buttonCompute.addActionListener(this);
    buttonNew.addActionListener(this);
    buttonClose.addActionListener(this);
    TermAndRate.addActionListener(this);
    jTextFieldMortgageAmt.addActionListener(this);
    jPanelErrorOutput = new JPanel();
    jLabelErrorOutput = new JLabel();
    FlowLayout error = new FlowLayout();
    jPanelErrorOutput.setLayout(error);
    //pane.add(jLabelErrorOutput);not worrying about this one
    //setContentPane(pane);
    pack();
    setVisible(true);
  }instead of
if (TermAndRate.getSelectedItem() == "7 years at 5.35%") ;
Term = 7;
IntRate = 5.35;
you would be better off setting up arrays
int[] term = {7,15,30};
double[] rate = {5.35,5.50,5.75};
then using getSelectedIndex()
int loan = TermAndRate.getSelectedIndex()
Term = term[loan];
IntRate = rate[loan];