java - How does Junit @Rule work?

Question

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.

Answer 1

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.