How to resolve this issue?

Error:

Exception in thread "main" java.lang.NullPointerException

at Program8.sort(Program8.java:25)

at Program8.main(Program8.java:107)

Program8:

import java.io.File;

import java.io.FileNotFoundException;

import java.util.Scanner;

public class Program8 {

public static void sort(OfficeCustomerClass customersObject[])

{

int min;

for(int i=0;i

{

min=i;

for(int j=i+1;j

if(customersObject[j].getId()< customersObject[min].getId())

min=j;

if(min != i)

{

OfficeCustomerClass temp = customersObject[i];

customersObject[i] = customersObject[min];

customersObject[min] =temp;

}

}

}

public static void main(String[] args) throws FileNotFoundException {

OfficeCustomerClass customersObject[];

File file = new File("OfficeCustomerClass.txt");

Scanner fileScan = new Scanner(file);

int records;

records = Integer.parseInt(fileScan.nextLine());

customersObject = new OfficeCustomerClass[records];

int index = 0;

String nameElement="", email="",taxLiabilityElement="";

int id=0;

double bill=0;

while(fileScan.hasNext() && index < records)

{

try {

nameElement = fileScan.nextLine();

id = Integer.parseInt(fileScan.nextLine());

bill = Double.parseDouble(fileScan.nextLine());

email = fileScan.nextLine();

taxLiabilityElement = fileScan.nextLine();

double tax = Double.parseDouble(taxLiabilityElement);

customersObject[index] = new TaxNonExemptCustomer(nameElement,id,bill,email,tax);

index++;

}catch(NumberFormatException ex)

{

customersObject[index] = new TaxExemptCustomerClass(nameElement,id,bill,email,taxLiabilityElement);

index++;

}

}

fileScan.close();

sort(customersObject);

int page = 0;

int i=0;

while(i

page++;

int j=0;

System.out.println(" \t Office Supplies Inc \t Page : "+page);

System.out.println("Customer Name \t ID \t Bill balance \t email \t\t Tax Liability");

// displaying 2 records per page, change this to display the desired number of records per page

while(i < customersObject.length && j <2) {

System.out.println( customersObject[i]);

i++;

j++;

}

}

}

}

TaxNonExemptCustomer

public class TaxNonExemptCustomer extends OfficeCustomerClass{

private double taxLiabilityElement;

public TaxNonExemptCustomer()

{

super();

taxLiabilityElement=0;

}

public TaxNonExemptCustomer(String nameElement, int id, double billBalanceElement, String email,double taxLiabilityElement)

{

super(nameElement,id,billBalanceElement,email);

settaxLiabilityElement(taxLiabilityElement);

}

public void settaxLiabilityElement(double taxLiabilityElement)

{

this.taxLiabilityElement = ((taxLiabilityElement*getbillBalanceElement())/100);

}

public double gettaxLiabilityElement()

{

return taxLiabilityElement ;

}

public String toString()

{

return(super.toString()+"\t"+taxLiabilityElement);

}

}

TaxExemptCustomer

public class TaxExemptCustomerClass extends OfficeCustomerClass{

private String taxLiabilityElement;

public TaxExemptCustomerClass()

{

super();

taxLiabilityElement= "";

}

public TaxExemptCustomerClass(String nameElement, int id, double billBalanceElement, String email,String taxLiabilityElement)

{

super(nameElement,id,billBalanceElement,email);

this.taxLiabilityElement = taxLiabilityElement;

}

public void settaxLiabilityElement(String taxLiabilityElement)

{

this.taxLiabilityElement = taxLiabilityElement;

}

public String gettaxLiabilityElement()

{

return taxLiabilityElement;

}

public String toString()

{

return (super.toString()+"\t"+taxLiabilityElement);

}

}

Input File:

100 Amazon 900 20000.00 purchasing@amazon.com 0.08 Nordstrom 210 50000.00 purchasing@nordstrom.com 0.07 Rutgers 010 32000.00 purchasing@rutgers.edu education Alamo 520 23000.00 purchasing@alamo.com 0.05 Kean 001 158000.50 purchasing@kean.edu education Allied 100 85300.00 purchasing@allied.com 0.06 JoesInc 950 999999.00 purchasing@joesinc.com 0.03 BostonU 697 340020.23 purchasing@tufts.edu education

OfficeCustomerClass

import java.io.FileNotFoundException;

import java.util.Scanner;

public class OfficeCustomerClass {

private String nameElement;

private int id;

private double billBalanceElement;

private String email;

public OfficeCustomerClass()

{

nameElement="";

id=0;

billBalanceElement=0;

email="";

}

public OfficeCustomerClass(String nameElement, int id, double billBalanceElement, String email)

{

this.nameElement = nameElement;

this.id = id;

this.billBalanceElement = billBalanceElement;

this.email = email;

}

public void setnameElement(String nameElement)

{

this.nameElement = nameElement;

}

public void setId(int id)

{

this.id = id;

}

public void setbillBalanceElement(double billBalanceElement)

{

this.billBalanceElement = billBalanceElement;

}

public void setEmail(String email)

{

this.email = email;

}

public String getnameElement()

{

return nameElement;

}

public int getId()

{

return id;

}

public double getbillBalanceElement()

{

return billBalanceElement;

}

public String getEmail()

{

return email;

}

public String toString()

{

return (nameElement+"\t"+id+"\t"+billBalanceElement+"\t\t"+email);

}

}