Also do all of the sub classes have the same methods? because if you define it as a doctor and dont have something like isJanitor() then it will give you an error.

Try testing it without using the employee class. does it still give you that error?

Your child class should extend object... unless employee does? try doing that... the odd thing is that technically everything is an object right?

hmm..
can you show me part of your code? say one of the classes and how your initializing the object.

in your child classes did you extend object?

You can do Double.parseDouble instead of Integer.parseInt

hmm,
There is no clean way i can think of, but you can do

try{
int num=Integer.parseInt(firstDenominator.getText());
//if it gets to here its valid
}catch(NumberFormatException e){
//invalid...

basically you need to check if they have a value. if the enter nothing then the string will be null or "". If you try to set a integer equal to null, you will get an exception, so you need to check...

import javax.swing.JOptionPane;

public class GPA {

private double gpa = 0.0;

public GPA() {
}

public String UserInput(){

please use code tags :-)


public class MyNew extends JFrame implements ActionListener
{
public static void main(String[] args)
{
publicMyNew start= newMyNew();
...

can you make those photos larger?

// Displaying multiple strings
import javax.swing.*; // to use JOptionPane.show InputDialog box
public class a3
{
public static void main( String[] args )//args is an array. to...

also isnt the main methos suppose to be
main(String[] args)

double
totalPrice = 0, // the sum of calculated devices
devices = 0, // the number of devices wanted
salesTax = 0, // the calculated sales tax...

if( devices < 30 )
cost = "46.00";
else if( devices >= 30 && devices< 70 )
cost = "43.00";
else if(...