Java for Testers Interview Questions for Automation Testing

Overloading: same method name, different parameters, in the same class (compile time). Overriding: a subclass redefines a parent method with the same signature (runtime polymorphism). WebDriver driver = new ChromeDriver() is runtime polymorphism.

Encapsulation: private locators with public page methods. Inheritance: pages extend a BasePage. Polymorphism: the WebDriver interface for different browsers. Abstraction: utility layers hiding Selenium details.

ArrayList stores an ordered list (e.g. all product names on a page). HashMap stores key–value pairs (e.g. test data or config properties).

String r = new StringBuilder(s).reverse().toString(); // or loop from the last index and append each character

String is immutable — every change creates a new object. StringBuilder is mutable and faster for repeated changes (not thread-safe; StringBuffer is).