How to correctly shut down a JUnit-Runner?

I made my own JUnit-Runner by implementing org.junit.runner.Runner, so that I can run my UnitTests with them using the @RunWith-Annotation.

It lookes somewhat like this:

public class MyRunner extends Runner {

    private Context myContext;
    myContext.init();
    private final BlockJUnit4ClassRunner runner;

    public MyRunner(final Class<?> clazz) throws InitializationError {
        myContext = new Context();

        runner = new BlockJUnit4ClassRunner(clazz);
    }

    @Override
    public void run(final RunNotifier notifier) {
        runner.run(notifier);
    }

    @Override
    public Description getDescription() {
        return runner.getDescription();
    }

    public void filter(final Filter filter) throws NoTestsRemainException {
        runner.filter(filter);
    }
}

To clean up resources, I have to shut down MyContext by calling MyContext.close(). Where should I invoke this so that my resources are cleand up after the tests have run?

Where should I invoke this so that my resources are cleand up after the tests have run ?

UPDATED MY ANSWER, you can use org.junit.runner.notification.RunListener as shown below:

(1) Create your own RunListener class:

public class MyRunnerListener extends RunListener {
    private Context context;

    public MyRunnerListener(Context context) {
        this.context = context;
    }

     void   testRunFinished(Result result)  {
          context.close();
     }
}

(2) Use the MyRunnerListener inside MyRunner :

public class MyRunner extends Runner {

    private Context myContext;
    MyRunnerListener runnerListener;
    private final BlockJUnit4ClassRunner runner;

    public MyRunner(final Class<?> clazz) throws InitializationError {
        myContext = new Context();
        myContext.init();
        runnerListener = new MyRunnerListener(myContext);

        runner = new BlockJUnit4ClassRunner(clazz);
    }

    @Override
    public void run(final RunNotifier notifier) {
        notifier.addListener(runnerListener);
        runner.run(notifier);
    }

    @Override
    public Description getDescription() {
        return runner.getDescription();
    }

    public void filter(final Filter filter) throws NoTestsRemainException {
        runner.filter(filter);
    }
}

P.S.: If you don't want to use the Runner, then you can follow the answer from Markus (which uses TestRule, NOT TestRunner).