org.junit
Annotation Type Rule

@Retention(value=RUNTIME)
@Target(value=FIELD)
public @interface Rule

Annotates fields that contain rules. Such a field must be public, not static, and a subtype of TestRule. The Statement passed to the TestRule will run any Before methods, then the Test method, and finally any After methods, throwing an exception if any of these fail. If there are multiple annotated Rules on a class, they will be applied in an order that depends on your JVM's implementation of the reflection API, which is undefined, in general. For example, here is a test class that creates a temporary folder before each test method, and deletes it after each:

 public static class HasTempFolder {
        @Rule
        public TemporaryFolder folder= new TemporaryFolder();
 
        @Test
        public void testUsingTempFolder() throws IOException {
                File createdFile= folder.newFile("myfile.txt");
                File createdFolder= folder.newFolder("subfolder");
                // ...
        }
 }
 

For more information and more examples, see TestRule. Note: for backwards compatibility, this annotation may also mark fields of type MethodRule, which will be honored. However, this is a deprecated interface and feature.