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Table of Contents:

What is Inheritance in Java?

How Inheritance Works (Basics & Types)

How It Matters in Selenium Frameworks

Best Practices for Testers

Why This Matters

1. What is Inheritance in Java?
‑ Inheritance in Java is the mechanism by which one class (the “child” or subclass) inherits fields and methods of another (the “parent” or superclass).
‑ It allows reuse of code: you write common behaviour in a base class, and derived classes automatically get it, reducing duplication.
‑ For automation testers using Java + Selenium WebDriver, inheritance helps you structure your framework so that setup, teardown, utilities, and common logic live in a base class and are inherited by specific test classes or page‑objects.

2. How Inheritance Works (Basics & Types)

Use the extends keyword: class Child extends Parent { … } means Child inherits Parent’s accessible methods and fields.

Types of inheritance in Java (as seen from a conceptual view):

Single inheritance — one child, one parent.

Multilevel inheritance — child inherits from parent, which itself inherits from another.

Hierarchical inheritance — multiple children inherit from one parent.

Notes for testers: Java does not allow multiple inheritance of classes (i.e., a class cannot extends two classes) to avoid ambiguity.

Example scenario (automation context):

public class BaseTest {
protected WebDriver driver;
@BeforeClass
public void setup() {
// driver init, config
}
@AfterClass
public void teardown() {
driver.quit();
}
}

public class LoginTest extends BaseTest {
@Test
public void validLogin() {
driver.get("…");
// test logic
}
}


Here LoginTest inherits setup/teardown from BaseTest.

3. How It Matters in Selenium Frameworks

Maintain a central BaseTest class with common logic (browser setup, configuration, driver lifecycle) and test classes inherit it. This avoids repeating that logic in every test.

Similarly, a BasePage class in a Page Object Model (POM) framework holds shared methods (e.g., click, enterText, waitForPageLoad) and each page class inherits from it. This keeps your page‑objects DRY (Don’t Repeat Yourself).

Inheritance helps you enforce consistent architecture: one place to manage changes (in the base class) and many child classes pick it up. For example, if you change how the driver is initialized, you update BaseTest not each test class.

It supports scalability: as you add more tests and pages, they simply extend the base classes and only define what’s unique.

Designers of frameworks also use inheritance to manage utility/helper classes: e.g., a BaseUtility class with methods like takeScreenshot() or logStep() that other helper classes extend.

4. Best Practices for Testers

Keep it simple: Use inheritance only where there is a clear “is‑a” relationship (e.g., LoginTest is a BaseTest). Avoid deep or complicated inheritance chains just for reuse.

Ensure your base classes stay lean and focused: BaseTest should only contain what all tests need (setup/teardown/config). Don’t overload it.

Use protected visibility for inherited members that child classes need, but hide unnecessary details (via private) in base classes.

Do not override base class code just for the sake of override—override only when the child class needs to customize behavior.

Combine inheritance with composition when appropriate: If a test class just uses utilities rather than inherits behavior, sometimes composition is better.

When using inheritance in page‑objects:

BasePage holds the WebDriver reference, common wrapper methods, maybe navigation or common parts of UI.

Each concrete page class extends BasePage and adds page‑specific methods and locators.

Review base class changes carefully: Because many subclasses depend on it, changes in base can ripple through entire framework. Use regression tests.

Avoid “god” base classes that do everything: If the class becomes huge with many unrelated methods, break it down logically.

Document your inheritance strategy overall: why you created BaseTest, what should go there, what should be in child tests. It helps new team members.

5. Why This Matters
‑ Without a disciplined inheritance approach, your automation framework will devolve into repeated boilerplate code, inconsistent setup across tests, and higher maintenance effort.
‑ Strong use of inheritance (with OOP principles) ensures your framework is modular, maintainable, scalable—tests grow but architecture stays robust.
‑ For you as a tester or SDET, leveraging OOP and inheritance elevates your value: you’re building frameworks, not just scripts.
‑ As automation suites grow (multiple modules, browsers, platforms), having base classes and inheritance means you can extend quickly without rewriting large chunks.


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