Java: Return statement in a decision structure for Payroll class?

I have to make a class called Payroll and a PayrollDemo class to go along with it.

This is my code so far for the Payroll Class:

public class Payroll {
   private double hoursWorked, payRate;

   public Payroll() {
   hoursWorked = 0.0;
   payRate = 0.0;
}

public void setHoursWorked(double hours) {
hoursWorked = hours;
}

public void setPayRate(double rate) {
 payRate = rate;
}

public double getHoursWorked() {
return hoursWorked;
 }

public double getPayRate() {
return payRate;
}

public String calcPay() {
if (hoursWorked <= 40) {
  double grossPay = hoursWorked * payRate;

  System.out.println("Regular Pay\n============\nHours: " + getHoursWorked() + "\nRate: $" + getPayRate() + "Gross Pay = $" + grossPay);

} else if (hoursWorked > 40) {
    double grossPay = (40 * payRate) + ( (hoursWorked - 40) * payRate * 1.5 );

    System.out.println("Pay With Overtime\n=================\nHours: " + getHoursWorked() + "\nRate: $" + getPayRate() + "Regular Pay = $" + (40 * payRate) + "\nOvertime Hours = " + (hoursWorked - 40) + "\nOvertime Pay Rate = $" + (payRate * 1.5) + "Overtime Pay = $" + ( (hoursWorked - 40) * payRate * 1.5 ) + "Gross Pay = $" + grossPay);
 }
}  
}

The problem is that I get an error: return statement missing. I tried replacing both Println with a return instead, but that did not work. So I was just wondering how to fix the program.