JUnit4 : Test a shutdown hook is called

I have a method which adds a shutdown hook. I need to test (via JUnit) that the code executed in the hook is called :

public void myMethod(){
    Runtime.getRuntime().addShutdownHook(new Thread() {

        @Override
        public void run() {
            ... code to test ...
        }
    });
}

How can I simulate a shutdown in my unit test ?