I want to write test cases for a bulk of code, I would like to know details of JUnit @Rule annotation feature, so that I can use it for writing test cases. Please provide some good answers or links, which give detailed description of its functionality through a simple example.
Rules are used to add additional functionality which applies to all tests within a test class, but in a more generic way.
For instance, ExternalResource executes code before and after a test method, without having to use @Before and @After. Using an ExternalResource rather than @Before and @After gives opportunities for better code reuse; the same rule can be used from two different test classes.
The design was based upon: Interceptors in JUnit
For more information see JUnit wiki : Rules.