### Question:
EventManager { public <T extends EventData> void removeListener (int typeID, EventListener<T> listener) { Objects.requireNonNull(listener); Array<EventListener> list = this.listenerMap.get(typeID); if (list != null) { list.removeValue(listener, false); } } EventManager(String name, boolean setAsGlobal); void update(); void update(int maxMillis); void queueEvent(EventData event); void triggerEvent(EventData event); void addListener(int typeID, EventListener<T> listener); void removeListener(int typeID, EventListener<T> listener); static final EventManager getInstance();  }### Answer:
@Test (expected = NullPointerException.class) public void testRemoveNullListener () { EventManager manager = new EventManager("test", false); manager.removeListener(1, null); }