What do i do when I am getiting Java.lang.NullPointerException? [duplicate]

I was wondering if this platform could be of any help. I was running some test in eclipse, even though i have defined the test in a step definition, define the page object class, when i run the test it opens the browser and perform the first step but fail on the 2nd step (I click on the start button)i get the NullpointerException.

[DEBUG] Adding key: http://localhost:48614 for channel [id: 0x69f1164a, L:/127.0.0.1:59373 - R:localhost/127.0.0.1:48614]
  
Given I am from Wales and i launch the checkertool                         # 

stepDefinitions.steps.i_am_from_wales_and_i_launch_the_checkertool()
When I click on the start button                                           # stepDefinitions.steps.i_click_on_the_start_button()
[DEBUG] Entry count for : http://localhost:59374 : 1
[DEBUG] Entry count for : http://localhost:48614 : 1
java.lang.NullPointerException  at org.openqa.selenium.support.pagefactory.DefaultElementLocator.findElement(DefaultElementLocator.java:70)
at org.openqa.selenium.support.pagefactory.internal.LocatingElementHandler.invoke(LocatingElementHandler.java:39)
    at com.sun.proxy.$Proxy15.click(Unknown Source)
    at pageObjects.loginPage.Clicknocookies(loginPage.java:30)
    at stepDefinitions.steps.i_click_on_the_start_button(steps.java:36)
    at ✽.I click on the start button(file:///C:/Users/aka_s/eclipse-workspace/nhsbsa/./Features/Walesticket.feature:5)

  And I choose my country                                                    # stepDefinitions.steps.i_choose_my_country()
  And I input my date of birth                                               # stepDefinitions.steps.i_input_my_date_of_birth()
  When I choose if i live with my partner or not                             # stepDefinitions.steps.i_choose_if_i_live_with_my_partner_or_not()
  And I choose whether i claim tax benefit                                   # stepDefinitions.steps.i_choose_whether_i_claim_tax_benefit()
  And I choose whether i am pregnant or given birth in the last twelve month # stepDefinitions.steps.i_choose_whether_i_am_pregnant_or_given_birth_in_the_last_twelve_month()
  And I choose if i have injury caused by service                            # stepDefinitions.steps.i_choose_if_i_have_injury_caused_by_service()
  And I choose if i am diabetic or not                                       # stepDefinitions.steps.i_choose_if_i_am_diabetic_or_not()
  When I choose if myself or my family has gloucoma                          # stepDefinitions.steps.i_choose_if_myself_or_my_family_has_gloucoma()
  And I choose if i live permanently in a care home                          # stepDefinitions.steps.i_choose_if_i_live_permanently_in_a_care_home()
  And I choose if i have savings more than sixteen thousand pounds           # stepDefinitions.steps.i_choose_if_i_have_savings_more_than_sixteen_thousand_pounds()
  Then I should get a result of whether I will get help or not               # stepDefinitions.steps.i_should_get_a_result_of_whether_i_will_get_help_or_not()

Also find the features files

Feature: Wales Test Ticket

Scenario: Test to Validate Wales Test Ticket
 Given I am from Wales and i launch the checkertool
 When I click on the start button
 And I choose my country
 And I input my date of birth
 When I choose if i live with my partner or not
 And I choose whether i claim tax benefit
 And I choose whether i am pregnant or given birth in the last twelve month
 And I choose if i have injury caused by service
 And I choose if i am diabetic or not
 When I choose if myself or my family has gloucoma
 And I choose if i live permanently in a care home
 And I choose if i have savings more than sixteen thousand pounds
 Then I should get a result of whether I will get help or not

Kindly find below the step definition for the 1st and 2nd scenario. package stepDefinitions;

import static org.junit.Assert.assertEquals;

import org.openqa.selenium.WebDriver;

import io.cucumber.java.en.*;
import pageObjects.birthPage;
import pageObjects.countryPage;
import pageObjects.diabetesPage;
import pageObjects.glaucomaPage;
import pageObjects.injuryPage;
import pageObjects.loginPage;
import pageObjects.partnerPage;
import pageObjects.pregnantPage;
import pageObjects.residencePage;
import pageObjects.resultPage;
import pageObjects.savingsPage;
import pageObjects.taxbenefitPage;
import utilities.Executescript;
import utilities.browserDriver;

public class steps 

    {
    
        public WebDriver driver;
        public loginPage login = new loginPage(driver) ;
    
        @Given("I am from Wales and i launch the checkertool")
        public void i_am_from_wales_and_i_launch_the_checkertool() {
            driver = browserDriver.getDriver();
        }
    

        @When("I click on the start button")
        public void i_click_on_the_start_button()  throws Exception{
            login.Clicknocookies();
            Executescript.JavascriptexecutorCoordinate(driver);
            login.Clickstartbutton();
        }
    



Find below Page object for the loginpage.

public class loginPage {

    WebDriver driver;

    // Constructor for the webdriver
    public loginPage(WebDriver driver) {
        this.driver = driver;
        PageFactory.initElements(driver, this);
    }

    // Collection of web element

    @FindBy(how = How.ID, using = "next-button")
    private WebElement startbutton;
    
    @FindBy(how = How.ID, using = "nhs-global-header")
    private WebElement donotusecookies;

    public void Clicknocookies() {
        donotusecookies.click();
    }
    public void Clickstartbutton() {
        startbutton.click();
    }

}