### Question:
World { public WorldObjectList getWorldObjects() { return worldObjects; } World();  World(Zone... zones); WorldObjectList getWorldObjects(); void update(); Map<Integer, Zone> getZones(); long getLastUpdateCompleted(); long getLastUpdateStarted();  }### Answer:
@Test(expectedExceptions = NullPointerException.class) public void testAddNullObject() { World world = WorldUtils.createDefaultWorld(); world.getWorldObjects().add(null); }