Junit : how to add listener, and how to extends RunListener to override behaviors while failed

http://junit.sourceforge.net/javadoc/org/junit/runner/notification/RunListener.html

org.junit.runner.notification
Class RunListener

java.lang.Object   org.junit.runner.notification.RunListener 

---

public class RunListener
extends java.lang.Object

If you need to respond to the events during a test run, extend RunListener and override the appropriate methods. If a listener throws an exception while processing a test event, it will be removed for the remainder of the test run.

For example, suppose you have a Cowbell class that you want to make a noise whenever a test fails. You could write:

 public class RingingListener extends RunListener {
    public void testFailure(Failure failure) {
       Cowbell.ring();
    }
 }

To invoke your listener, you need to run your tests through JUnitCore.

 public void main(String... args) {
    JUnitCore core= new JUnitCore();
    core.addListener(new RingingListener());
    core.run(MyTestClass.class);
 }