Here's the updated code, and the error message is:
"Exception in thread "main" java.lang.NullPointerException at Employee.main(Employee.java:109)"
public static void main(String[] args) {
//declare an object
Scanner input = new Scanner(System.in);
final int size = 100; //max array size
int numEmployee=0; //number of array entries
int i;
int choice=0;
Employee [] employeeData = new Employee[size]; //an array of objects
employeeData[numEmployee] = new Employee();
while(choice!=3){
System.out.println("1. Enter new employee data");
System.out.println("2. Display employee data");
System.out.print("3. Quit \n=> ");
choice = input.nextInt();
if(choice == 1){
employeeData[numEmployee].getUserEntry(); //******** NPE occurs here *******
numEmployee++;
}else if(choice == 2){
for(i = 0; i<numEmployee; i++);
System.out.println(employeeData[i].getFirstName()+"\t"+employeeData[i].getLastName());
}else if(choice == 3){
System.out.println("You have quit.");
}else{
System.out.println("Invalid entry. Please try again.");
} //close if
} //close while
} //close main