I have a class with an array of objects and getting a null p

I have a class with an array of objects and getting a null pointer exception.

How do I fix the nullpointerexception on this array of objects?

When addEmployee is called I am getting this error.

Exception in thread \"main\" java.lang.NullPointerException
at EmployeeList.addEmployee(EmployeeList.java:42)
at EmployeeDriver.main(EmployeeDriver.java:124)

Here is the Driver class

Solution

Here is your modified driver class... you code is lot of messy and push unwanted do while loops , not closed case statements properly..

import java.util.Scanner;

public class EmployeeDriver {

public static void main(String args[]) {
// variables to hold user input values
int mainInput = -1; //Input for main menu
int empType = -1; //Input for employee type
int subInput1 = -1; //Input for submenu
int subInput2 = -1; //Input for sub-submenu
int empNum; //Input for employee number

int index; //Index of a specific Employee object in the list

Scanner in = new Scanner(System.in);

EmployeeList empMgr = new EmployeeList(); //The EmployeList object

// options for the main menu
String mainMenuOptions[] = {
\"Quit\",
\"Add Employee\",
\"Process Employees by Type Submenu\",
\"Remove Employee\",
\"Sort Employees\",
\"Calculate Weekly Payout\",
\"Calculate Bonus\",
\"Annual Raises\",
\"Reset Week\"};
// options for the \'process employee by type\' menu
String empTypeMenuOptions[] = {
\"Back\",
\"Hourly Employees\",
\"Salary Employees\",
\"Commission Employees\"};

// create the main menu and employee Menu objects
Menu mainMenu = new Menu(mainMenuOptions);
Menu empTypeMenu = new Menu(empTypeMenuOptions);

//Main control loop, keep coming back to the
//Main menu after each selection is finished
do {
// Display all current employees in the list
empMgr.listAll();

//Run the main menu to display options, read, validate and return the user\'s choice
System.out.println(\"Main Menu\");
mainInput = mainMenu.runMenu();

//Perform the Main Menu action requested by the user
switch (mainInput) {
//Add Employee main menu option
case 1:
// declare temporary variables for user input of employee values
String fName = null,
lname;
char gender,
f;
boolean ft = true;
double amount;

// get the employee type
do {
System.out.println(\"\ 1. Hourly\");
System.out.println(\"2. Salary\");
System.out.println(\"3. Commission\");
System.out.print(\"Enter Choice: \");
empType = in.nextInt();
if (empType < 1 || empType > 3) {
System.out.println(\"Invalid Choice. Try Again!\");
}
} while (empType < 1 || empType > 3);

System.out.print(\"Enter Last Name: \");
lname = in.next();
System.out.print(\"Enter First Name: \");
fName = in.next();
System.out.print(\"Enter Gender: \");
gender = in.next().charAt(0);

// ask for employee number
// search employee list for existing employee with that number
// if number already exists, display an error message
int en_index = -1;
do {
System.out.print(\"Enter Employee Number: \");
empNum = in.nextInt();
// if empNum in range then check employee list to determine if
// employee number already exists
if (empNum >= 1 && empNum <= 99999) {
en_index = empMgr.getIndex(empNum);
if (en_index != -1) {
System.out.println(\"Employee number already used - Choose a new number\");
}
} else {
System.out.println(\"Employee number must be between 1 and 99999 inclusive\");
}

} while (en_index != -1 || (empNum < 1 || empNum > 99999));

// determine if employee is a full time employee
System.out.print(\"Full Time? (y/n): \");
f = in.next().charAt(0);
if (f == \'n\' || f == \'N\') {
ft = false;
}
System.out.println(\"1. Add Hours\");
System.out.println(\"0. Back\");
System.out.print(\"\ Enter Choice: \");
subInput2 = in.nextInt();
if (subInput2 < 0 || subInput2 > 1) {
System.out.println(\"Invalid Choice! Choose Again.\");
}

if (subInput2 == 1) {
double hours = 0.0;
System.out.println(\"Employee Number: \");
empNum = in.nextInt();
index = empMgr.getIndex(empNum);
if (index != -1) {
System.out.print(\"Enter Hours: \");
hours = in.nextDouble();
empMgr.increaseHours(index, hours);
} else {
System.out.println(\"Employee not found!\");
}

}
break;

case 2: // salary employee
// display salaried employees
do {
System.out.println();
empMgr.listSalary();
System.out.println(\"0. Back\");
System.out.print(\"\ Enter Choice: \");
subInput2 = in.nextInt();
if (subInput2 != 0) {
System.out.println(\"Invalid Choice! Choose Again.\");
}
} while (subInput2 != 0);
break;

case 3: // commission employee
// display commission employees and allow sales to be updated
do {

// Prompt the user for the specific information required for the employee type
if (empType == 1) {
System.out.print(\"Enter wage: \");
} else if (empType == 2) {
System.out.print(\"Enter salary: \");
} else {
System.out.print(\"Enter rate: \");
}
amount = in.nextDouble();

// add the employee to the list of employees
System.out.println(\"Enter first name: \");
fName = in.nextLine();
System.out.println(\"Enter last name: \");
lname = in.nextLine();
System.out.println(\"Enter employee number: \");
empNum = in.nextInt();
System.out.println(\"Enter ft: \");
ft = in.nextBoolean();
if (empMgr.addEmployee(empType, fName, lname, \'m\', empNum, ft, amount)) {
System.out.println(\"Employee Added to List\");
} else {
System.out.println(\"Employee NOT added to List\");
}

} while (subInput2 != 0);
}
empType = empTypeMenu.runMenu();
switch (empType) {
case 1: // hourly employee
// display hourly employees and allow hours to be updated
do {
System.out.println();
empMgr.listHourly();
do {
System.out.println();
empMgr.listCommission();
System.out.println(\"1. Add Sales\");
System.out.println(\"0. Back\");
System.out.print(\"\ Enter Choice: \");
subInput2 = in.nextInt();
if (subInput2 < 0 || subInput2 > 1) {
System.out.println(\"Invalid Choice! Choose Again.\");
}
} while (subInput2 < 0 || subInput2 > 1);

if (subInput2 == 1) {
double sales = 0.0;
System.out.println(\"Employee Number: \");
empNum = in.nextInt();
index = empMgr.getIndex(empNum);
if (index != -1) {
System.out.print(\"Enter Sales: \");
sales = in.nextDouble();
empMgr.increaseSales(index, sales);
} else {
System.out.println(\"Employee not found!\");
}
}
} while (subInput2 != 0);
break;
//Process Employee by Type main menu option
case 2:
do {
//Call emptypeMenu to Display \'process employee by type\' menu options and reads,
//validates and returns the user\'s choice
empType = empTypeMenu.runMenu();

switch (empType) {
case 1: // hourly employee
// display hourly employees and allow hours to be updated

do {
System.out.println();
empMgr.listHourly();
do {
System.out.println();
empMgr.listCommission();
System.out.println(\"1. Add Sales\");
System.out.println(\"0. Back\");
System.out.print(\"\ Enter Choice: \");
subInput2 = in.nextInt();
if (subInput2 < 0 || subInput2 > 1) {
System.out.println(\"Invalid Choice! Choose Again.\");
}
} while (subInput2 < 0 || subInput2 > 1);

if (subInput2 == 1) {
double sales = 0.0;
System.out.println(\"Employee Number: \");
empNum = in.nextInt();
index = empMgr.getIndex(empNum);
if (index != -1) {
System.out.print(\"Enter Sales: \");
sales = in.nextDouble();
empMgr.increaseSales(index, sales);
} else {
System.out.println(\"Employee not found!\");
}
}
} while (subInput2 != 0);
break;
}

} while (empType != 0);
case 3:
System.out.print(\"Enter Employee Number to Remove: \");
empNum = in.nextInt();
// if empNum exists in the list - remove it
index = empMgr.getIndex(empNum);
if (index != -1) {
empMgr.removeEmployee(index);
} else {
System.out.println(\"Employee not found in the list\");
}
break;

//Sort Employees main menu option
case 4:
// determine the sort method prefered by the user
do {
System.out.println(\"\ 1. Sort by Employee Number\");
System.out.println(\"2. Sort by Name\");
System.out.print(\"Enter Choice: \");
subInput1 = in.nextInt();
if (subInput1 < 1 || subInput1 > 2) {
System.out.println(\"Invalid Input! Choose again.\");
}
} while (subInput1 < 1 || subInput1 > 2);

// if the user requests to sort by employee number
// call sortByEmpNumber
// else
// call sortbyLastName
if (subInput1 == 1) {
empMgr.sortByEmpNumber();
} else {
empMgr.sortByLastName();
}
break;

//Calculate Total Weekly Payout main menu option
case 5:
System.out.println();
System.out.printf(\"Total weekly payout is $%.2f\ \", empMgr.calculatePayout());
break;

//Calculate Total Bonus paid to all employees main menu option
case 6:
double bonus = empMgr.holidayBonuses();
System.out.printf(\"Total holiday bonus payout is $%,.2f\ \", bonus);
break;

//Apply Annual Raises for all employees main menu option
case 7:
empMgr.annualRaises();
System.out.println(\"Annual Raises applied.\");
break;

//Reset the weeks sales and hours-worked values back to zero main menu option
case 8:
empMgr.resetAllWeeks();
System.out.println(\"Weekly values reset.\");
break;

//Exit (Quit) main menu option
case 0:
System.out.println(\"\ Thank you for using the Employee List!\ \");
}

} while (mainInput != 0);
}

}