How do you implement data-driven testing in Cucumber BDD?

Feature: Login Validation

  Scenario Outline: Login with multiple users
    Given the user is on the login page
    When the user enters "<username>" and "<password>"
    Then the result should be "<expected>"

    Examples:
      | username        | password    | expected          |
      | admin@test.com  | Admin@123   | Dashboard         |
      | user@test.com   | User@456    | Home Page         |
      | wrong@test.com  | badpass     | Invalid Credentials |
      | locked@test.com | Locked@123  | Account Locked    |

@When("the user enters {string} and {string}")
public void enterCredentials(String username, String password) {
    driver.findElement(By.id("email")).sendKeys(username);
    driver.findElement(By.id("password")).sendKeys(password);
}

@Then("the result should be {string}")
public void verifyResult(String expected) {
    assertTrue(driver.getPageSource().contains(expected));
}

Scenario: Register with full form data
  Given the user fills in the registration form:
    | Field     | Value             |
    | FirstName | John              |
    | LastName  | Doe               |
    | Email     | john@example.com  |
    | Mobile    | 9876543210        |
    | Password  | Test@123          |
  Then the user should be registered successfully

@Given("the user fills in the registration form:")
public void fillRegistrationForm(DataTable dataTable) {
    Map<String, String> formData = dataTable.asMap(String.class, String.class);

    driver.findElement(By.id("firstName")).sendKeys(formData.get("FirstName"));
    driver.findElement(By.id("lastName")).sendKeys(formData.get("LastName"));
    driver.findElement(By.id("email")).sendKeys(formData.get("Email"));
    driver.findElement(By.id("mobile")).sendKeys(formData.get("Mobile"));
    driver.findElement(By.id("password")).sendKeys(formData.get("Password"));
}

// Read from Excel using Apache POI
@When("the user tests login with external data")
public void loginWithExternalData() throws Exception {
    FileInputStream fis = new FileInputStream("testdata/login.xlsx");
    XSSFWorkbook workbook = new XSSFWorkbook(fis);
    XSSFSheet sheet = workbook.getSheetAt(0);

    for (Row row : sheet) {
        String username = row.getCell(0).getStringCellValue();
        String password = row.getCell(1).getStringCellValue();
        // perform login with each row
    }
    workbook.close();
}