There is an Object Repository notion in QTP (Quick Test Professional). By default, when a user records a test, the objects and their properties are saved in an Object Repository. This Object Repository is used by QTP to playback scripts. There is no default Object Repository concept in Selenium. This isn't to say that Selenium doesn't have an Object Repository. Even if there isn't one by default, we could make our own.
Objects are referred to as locators in Selenium (such as ID, Name, Class Name, Tag Name, Link Text, Partial Link Text, XPath, and CSS). A collection of objects is referred to as an object repository. Placing all the locators in a separate file is one technique to construct an Object Repository (i.e., properties file). The ideal method, however, is to use Page Object Model. Each web page is represented as a class in the Page Object Model Design Pattern. A class contains all of the items associated with a specific page of a web application.
