Unreachable catch block???? what is this???

Question

I have created a try-catch statement, I have also created a home made Invalid value exception class. I have also thrown the InvalidValueException in a calculate method in a seperate class. I am getting the error of unreachable catch block. Here is my code for this process. Please Help
private void runPayroll(List employees)
Collections.sort(employees, new PersonComparator());
// place the following code in a try-catch statement to check for the following errors
//- InvalidValue (the pay units must be a decimal number > 0)
try
double payRate = Double.parseDouble(jtfPayRate.getText());
catch (InvalidValueException ivEx)//THIS IS WHERE I AM GETTING MY ERROR
JOptionPane.showMessageDialog(this, "the pay units must be a decimal number > 0", "Error Message", JOptionPane.ERROR_MESSAGE);
return;
// loop through all of the employees in the collection
Iterator iterator = employees.iterator();
StringBuffer output = new StringBuffer("");
while (iterator.hasNext())
Employee employee = (Employee)iterator.next();
output.append( employee.toString() + "\n" );
//InvalidValueException class
public class InvalidValueException extends Exception
public  InvalidValueException(double payUnit)
  super(payUnit);  //I SM GETTING THE ERROR The constructor Exception (double) is undefined  PLEASE HELP
public String getLocalizedMessage()
return "Amount must be > 0";
//PayCheck class this is where I throw the exception
public abstract double calculate(double payUnit, double payRate)
throws InvalidValueException;
public void calculateTax() throws InvalidValueException
FICAOwed = grossPay * FICA;
federalOwed = grossPay * federalTax;
stateOwed = grossPay * stateTax;
}     

Answer 1

Sorry did not mean to post twice. I made some changed from the responses, but Iwas not getting this error.
I have changed the code to this but now I am getting an error because the getText() returns a String. I need to check for a valid double could you help me with this.
try
double payRate = jtfPayRate.getText();
catch (InvalidValueException ivEx)//THIS IS WHERE I AM GETTING MY ERROR
JOptionPane.showMessageDialog(this, "the pay units must be a decimal number > 0", "Error Message", JOptionPane.ERROR_MESSAGE);
return;
}