There is no secret that the start of something new is often difficult. Therefore, if you are on this page, I guess you are new to WebDriver or as it is also known Selenium 2.0
When you are going to change your job you must be ready for the interview. Yet not only on this occasion you should know answers to theoretical questions. A real professional keeps fundamental knowledge in mind even not being aware of it. One of such things in Java is the difference between abstract class and interface.