Below is my base class, for initializing and managing a Selenium WebDriver instance. This class ensures that a single WebDriver instance is created and configured, which can be reused across different tests.

Code:

public WebDriver getDriver() {
    if (driver == null) {
        synchronized (BaseClass.class) {
            if (driver == null) {
                WebDriverManager.chromedriver().setup();
                ChromeOptions options = new ChromeOptions();
                options.addArguments("--remote-allow-origins=*");
                Map<String, Object> prefs = new HashMap<>();
                prefs.put("profile.default_content_setting_values.popups", 2);
                options.setExperimentalOption("prefs", prefs);
                driver = new ChromeDriver(options);
                driver.manage().window().maximize();
                driver.manage().deleteAllCookies();
                driver.manage().timeouts().pageLoadTimeout(140, TimeUnit.SECONDS);
                objWait = new WebDriverWait(driver, Duration.ofSeconds(60));
            }
        }
    }
    return driver;
}

@BeforeClass
public void initializeDriver() {
    try {
        driver = getDriver();
        driver.get(Locators.URL);
        Thread.sleep(3000);
    } catch (Exception e) {
        System.out.println(" Exception in before class driver instantiation: " + e);
    }
}

Below is my GuestUser.java class public class GuestUser extends CommonUtils

code :
`

`public void guestUserActions() {
        try {
            enableEnableDelivery();
            refresh();
            deliveryAddress();
            CloseButtonForSignInPopup();
            disableEnableDelivery();
            refresh();
            writeConsole("Guest User delivery actions completed");
            enableEnablePickup();
            refresh();
            pickupAddress();
            CloseButtonForSignInPopup();
            disableEnablePickup();
            refresh();
            WaitTime(3);
            writeConsole("Guest User pickup actions completed");
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }``

for the above case I have created a test class to execute the script. GuestUser.Test

code:

public class GuestUserTest extends GuestUser implements Locators {
    CategoryPage categoryPage = new CategoryPage();

    @Test
    public void guestTest() throws Exception {
        guestUserActions();
        categoryPage.gettingInsideCategories();
    }

Output:
Exception java.lang.NullPointerException
Driver is not getting intialised properly when it is getting into the next method in @test
categoryPage.gettingInsideCategories(). Could anyone please help ?