What are Data Tables in Cucumber and what are their use cases?

When the user submits the following form data:
  | Field     | Value            |
  | FirstName | John             |
  | Email     | john@example.com |
  | Phone     | 9876543210       |

Scenario: Submit contact form
  When the user fills in the contact form with:
    | Name    | Alice Smith       |
    | Email   | alice@example.com |
    | Message | Hello, I need help |
  Then the form should be submitted successfully

Scenario: Verify product list
  Then the homepage should display these products:
    | Laptop   |
    | Phone    |
    | Tablet   |
    | Watch    |

Scenario: Create new user via API
  When I send a POST request to "/api/users" with:
    | Field    | Value          |
    | name     | John Doe       |
    | email    | john@test.com  |
    | role     | ADMIN          |
  Then the response status should be 201

import io.cucumber.datatable.DataTable;
import java.util.*;

// As Map<String,String> (key-value pairs)
@When("the user fills in the contact form with:")
public void fillForm(DataTable dataTable) {
    Map<String, String> data = dataTable.asMap(String.class, String.class);
    driver.findElement(By.id("name")).sendKeys(data.get("Name"));
    driver.findElement(By.id("email")).sendKeys(data.get("Email"));
}

// As List<String> (single column)
@Then("the homepage should display these products:")
public void verifyProducts(DataTable dataTable) {
    List<String> expectedProducts = dataTable.asList(String.class);
    for (String product : expectedProducts) {
        assertTrue(driver.getPageSource().contains(product),
            "Product not found: " + product);
    }
}

// As List<Map<String,String>> (multiple rows with headers)
@When("the admin creates these users:")
public void createUsers(DataTable dataTable) {
    List<Map<String, String>> users = dataTable.asMaps(String.class, String.class);
    for (Map<String, String> user : users) {
        createUser(user.get("name"), user.get("email"), user.get("role"));
    }
}