abstract class vs interface java
Interfaces specify what a class must do. It is the blueprint of the class. It is used to achieve total abstraction. We are using implements keyword for interface. Basic statement we all know in Selenium is WebDriver driver = new FirefoxDriver(); WebDriver itself is an Interface. So we are initializing Firefox browser using Selenium WebDriver. It means we are creating a reference variable of the interface and creating an Object. So WebDriver is an Interface and FirefoxDriver is a class. Sometimes we may come across a situation where we cannot provide implementation to all the methods in a class. We want to leave the implementation to a class that extends it. In that case we declare a class as abstract by using abstract keyword on method signature.For example in my framework I am using page object model design pattern and I keep all locators under Page class. I utilize this locators in tests but we can't see them in the tests. Literally we are hiding locators from the test. Abstraction is methodology of hiding implementation of internal details and showing the functionality to users. Also 1)Abstract classes cannot be instantiated 2)An abstarct classes contains abstract method, concrete methods or both. 3)Any class which extends abstarct class must override all methods of abstract class 4)An abstarct class can contain either 0 or more abstract method.