Selenium Interview Questions for 3 Years Experience (1970) — Mid-Level SDET Edition

Selenium 4 speaks the W3C WebDriver protocol natively (no JSON Wire Protocol). It includes Selenium Manager (auto-driver resolution), Chrome DevTools Protocol access, relative locators, and a fully-distributed Grid model. See our Selenium WebDriver Guide for the full architecture.

Selenium Manager (Selenium 4.6+) automatically detects the installed browser version and downloads the matching driver. You no longer need WebDriverManager. Just instantiate the driver:

WebDriver driver = new ChromeDriver();

Selenium 4 introduced position-based locators (above, below, toLeftOf, toRightOf, near):

import static org.openqa.selenium.support.locators.RelativeLocator.with;

WebElement password = driver.findElement(
    RelativeLocator.with(By.tagName("input")).below(emailField)
);

Selenium 4 exposes CDP for network interception, geolocation overrides, performance metrics and more:

ChromeDriver driver = new ChromeDriver();
driver.devTools.createSession();

// Capture network traffic
driver.devTools.send(Network.enable());

// Override geolocation
driver.devTools.send(Emulation.setGeolocationOverride(
    Optional.of(37.7749), Optional.of(-122.4194), Optional.of(100.0)
));

• Implicit wait: polls the DOM for N seconds on every element lookup.
• Explicit wait: waits for a specific condition on a specific element.

Best practice in 2026: avoid implicit waits, use only explicit waits.

Fluent wait is an explicit wait with a custom polling interval and a list of exceptions to ignore:

FluentWait<WebDriver> wait = new FluentWait<>(driver)
    .withTimeout(Duration.ofSeconds(15))
    .pollingEvery(Duration.ofMillis(500))
    .ignoring(NoSuchElementException.class);

• Re-locate the element after the DOM change.
• Use explicit waits to wait for the new element.
• Use try/catch with retry logic for known flaky interactions.

Each page is a class with locators as private fields and actions as public methods. Tests interact with page objects, never raw locators. Benefits: maintainability, readability, parallel authoring of tests and locators.

For the full POM pattern, see our Selenium WebDriver Guide.

A deprecated-but-still-common pattern that initializes Page Object elements using @FindBy annotations. Modern codebases prefer constructor-based POM without Page Factory.

Three approaches:

• TestNG parallel mode: parallel="methods" thread-count="4" in testng.xml.
• Selenium Grid: Hub + nodes on multiple machines.
• Cloud grid: BrowserStack, Sauce Labs, LambdaTest.

Grid has two components:

• Hub: receives test requests, distributes to nodes.
• Nodes: execute tests in registered browser/OS combos.

In Selenium 4, the Grid is fully distributed (no standalone hub-and-node model).

# docker-compose.yml
version: '3'
services:
  chrome:
    image: selenium/node-chrome:4.25
    shm_size: 2gb
    depends_on: [hub]
  hub:
    image: selenium/hub:4.25
    ports:
      - "4442:4442"
      - "4443:4443"
      - "4444:4444"

• Use explicit waits (not Thread.sleep).
• Isolate test data per test.
• Design for parallelism from day one.
• Use retry only as a last resort, with quarantining and dashboards.

@AfterMethod
public void tearDown(ITestResult result) {
    if (result.getStatus() == ITestResult.FAILURE) {
        TakesScreenshot ts = (TakesScreenshot) driver;
        File src = ts.getScreenshotAs(OutputType.FILE);
        FileUtils.copyFile(src, new File("screenshots/" + result.getName() + ".png"));
    }
    driver.quit();
}

A minimal GitHub Actions job:

- uses: actions/setup-java@v4
  with: { distribution: temurin, java-version: '17' }
- run: mvn -B test

See GitHub Actions + Selenium CI for the full pipeline.

ChromeOptions options = new ChromeOptions();
options.addArguments("--headless=new");
WebDriver driver = new ChromeDriver(options);

• Use cookies: log in once, save cookies, reuse in tests.
• Use API-based login: hit the auth API, capture the token, inject as a cookie.
• Use a dedicated test user.

Use TestNG parameters and a @BeforeMethod that reads the browser from config:

@Parameters("browser")
@BeforeMethod
public void setUp(String browser) {
    if (browser.equals("chrome")) driver = new ChromeDriver();
    else if (browser.equals("firefox")) driver = new FirefoxDriver();
}

driver.findElement(By.id("upload")).sendKeys("/path/to/file.png");

Configure Chrome to download to a specific directory without showing the dialog:

ChromeOptions options = new ChromeOptions();
Map<String, Object> prefs = new HashMap<>();
prefs.put("download.default_directory", "/tmp/downloads");
options.setExperimentalOption("prefs", prefs);

driver.switchTo().frame("iframe-name");
driver.findElement(By.id("inside-iframe")).click();
driver.switchTo().defaultContent();

Alert alert = driver.switchTo().alert();
alert.accept();  // OK
alert.dismiss(); // Cancel

JavascriptExecutor js = (JavascriptExecutor) driver;
js.executeScript("window.scrollTo(0, document.body.scrollHeight)");

TestNG has data providers, listeners, and dependency-based ordering built-in. JUnit 5 has similar features via extensions but with different syntax. See our Java for Selenium guide for the full comparison.

@DataProvider(name = "users")
public Object[][] users() {
    return new Object[][] {
        {"admin@example.com", "Sup3rSecret!"},
        {"viewer@example.com", "ViewerPass1!"}
    };
}

@Test(dataProvider = "users")
public void loginTest(String email, String password) { ... }

public class MyListener implements ITestListener {
    @Override
    public void onTestFailure(ITestResult result) {
        // Take screenshot, log failure
    }
}

Register in testng.xml:

<listeners>
    <listener class-name="com.qa.MyListener"/>
</listeners>

<dependency>
    <groupId>org.seleniumhq.selenium</groupId>
    <artifactId>selenium-java</artifactId>
    <version>4.25.0</version>
</dependency>

• Use external files (JSON, CSV, Excel).
• Use a database fixture for complex data.
• Generate random data with libraries like Java Faker.
• Never hardcode credentials.

• Code coverage: JaCoCo (Java), Istanbul (JS), Coverage.py (Python).
• Requirement coverage: traceability matrix in TestRail or Xray.
• Risk coverage: identify high-risk areas and ensure 100% test coverage.

• Quantify time saved (manual regression was 3 days, now 4 hours).
• Show defect escape rate reduction (from 8% to 1.5%).
• Show cycle time improvement (PR cycle from 48h to 14h).
• Show cost avoidance (one prevented P0 bug = $50k+ saved).

For the full interview prep, see our Software Testing Interview Questions Master List.