The annotation is used to configure a unit test that required Spring’s dependency injection.
From Spring Reference – 10. Unit Testing:
10.1 Creating a Unit Test Class
In order for the unit test to run a batch job, the framework must load the job’s ApplicationContext. Two annotations are used to trigger this:
@RunWith(SpringJUnit4ClassRunner.class): Indicates that the class should use Spring’s JUnit facilities.
@ContextConfiguration(locations = {…}): Indicates which XML files contain the ApplicationContext.