ComboBox help

[corbymaker]

I am trying to add a drop down combo box for my program but I am having trouble adding items to the combo box. can anyone tell me what i am doing wrong or what I need to add/change.

//imports required packages
import java.awt.*;                      //to create buttons
import javax.swing.*;                   //imports java swing
import java.awt.event.ActionEvent;      //imports event action events
import java.awt.event.ActionListener;   //imports event action listener for the event
import java.text.DecimalFormat;         //to import decimal format for money

class mortgageCalculatorMcCabe3 extends JFrame implements ActionListener {

	//Fields for user input
	JTextField principalAmount = new JTextField(15);
	JTextField yearlyInterestRate = new JTextField(15);
	JTextField numberOfYears = new JTextField(15);
	JTextField monthlyPayments = new JTextField(15);
	JLabel validateLabel = new JLabel();
	public JComboBox MortIntRate;

	/*Declaring and initializing variables*/
	int term = 0;
	double principleAmount = 0;
	String ArrayTerm [] = {"7", "15", "30"};
	String ArrayInterestRate [] = {"5.35", "5.5", "5.75"};

mortgageCalculatorMcCabe3() {
	
	//Sets the title at the top of program 
	super("Ryan's Mortgage Calculator");	
	
	Panel comboBox = new Panel();
	JComboBox interestRateList, termList;
	   
	//Sets the size of the Frame
	setSize(350, 225);
	setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	Container pane = getContentPane();
	FlowLayout flow = new FlowLayout(FlowLayout.RIGHT);
	pane.setLayout(flow);

	//Creates Labels and Fields for row 1 
	JPanel row1 = new JPanel();
	JLabel principalLabel = new JLabel("Loan Amount:");
	row1.add(principalLabel);
	row1.add(principalAmount);
	pane.add(row1);
	
	//Creates Labels and Fields for row 2
	JPanel row2 = new JPanel();
	JLabel numYearsLabel = new JLabel("Term of Loan(Years):");
	row2.add(numYearsLabel);
	row2.add(numberOfYears);
	pane.add(row2);

	////Creates Labels and Fields for row 3
	JPanel row3 = new JPanel();
	JLabel yearIntrateLabel = new JLabel("Interest Rate:");
	row3.add(yearIntrateLabel);
	row3.add(yearlyInterestRate);
	pane.add(row3);

	////Creates Labels and Fields for row 4
	JPanel row4 = new JPanel();
	JLabel monthlyPaymentsLabel = new JLabel("Total Monthly Payment:");
	row4.add(monthlyPaymentsLabel);
	row4.add(monthlyPayments);
	pane.add(row4);
	setContentPane(pane);
	setVisible(true);

	//Creates Labels and Fields for row 5
	JPanel row5 = new JPanel();
	JButton calculate = new JButton("Calculate");
	calculate.addActionListener(this);
	row5.add(calculate);
	pane.add(row5);
	JButton reset = new JButton("Clear");
	reset.addActionListener(this);
	row5.add(reset);
	pane.add(row5);
	JButton exit = new JButton("Exit");
	exit.addActionListener(this);
	row5.add(exit);
	pane.add(row5);
	
	termList = new JComboBox(ArrayTerm);
	termList.setSelectedIndex(0);
	termList.addItemListener(this);
		

		interestRateList = new JComboBox(ArrayInterestRate);
		interestRateList.setSelectedIndex(0);
		interestRateList.addItemListener(this);		

		/*Setup list*/
		comboBox.add(loanTerm);
		comboBox.add(termList);		
		comboBox.add(loanInterest);
		comboBox.add(interestRateList);
		
}
//This parts performs the Actions for the Calculate, Clear & Exit buttons
public void actionPerformed(ActionEvent event) {
	String command = event.getActionCommand();
		if (command == "Calculate")
			compute();

		if (command == "Clear")
			clearAllFields();
		
		if (command == "Exit")
			exit();}

void compute()
{

	try{

		validateLabel.setText("");
		validateLabel.validate();

	Double yearIntrate = new Double (yearlyInterestRate.getText());
	Double principal = new Double (principalAmount.getText());
	Integer numYears = new Integer (numberOfYears.getText());

	double payFreq = 12;
	double interestRateMonths;
	double monthlyPayment;
	double numPayments;

//results and formula's
interestRateMonths = (yearIntrate.doubleValue() / 100) / payFreq;
numPayments = payFreq * numYears.intValue();

double temp = Math.pow(1 + interestRateMonths, (-1*numPayments));
monthlyPayment = principal.doubleValue() * interestRateMonths / (1 - (temp));

//Format used to set two decimal places.
DecimalFormat currency = new DecimalFormat("$0.00");

monthlyPayments.setText(currency.format(monthlyPayment));

//if user submit non valid information it provides an error.
} catch(Exception error)
{
validateLabel.setText("Invalid Entry! Try again.");
}
}

//to clear the fields back to beginning
void clearAllFields(){
	principalAmount.setText("");
	yearlyInterestRate.setText("");
	numberOfYears.setText("");
	monthlyPayments.setText("");
}
//exit program
void exit(){
	System.exit(0);

}

public static void main(String[] arguments)
{
mortgageCalculatorMcCabe3 mortgageCalculatorMcCabe3 = new mortgageCalculatorMcCabe3 ();
      }
}//end program

[Razee Marikar]

What did you do to add items, and what error did you get?