java – 如何通过在数组中只引用它来使对象为null？

我在GameWorld中有一系列游戏对象,他们可以从那个世界中删除.问题是某些游戏对象引用了其他游戏对象.例如. Player类引用了Bird. Bird会从GameWorld中随机删除,但Player仍然会引用它.我目前进行空检查以检查GameObject是否仍然有效并且在世界上.但是,从数组中删除对象不会使该引用为null.那我怎么能把它变成空？

这是一个例子：

// GameWorld creates bird
ArrayList<Object> gameObjects = new ArrayList<>();
Object bird = new Object();
gameObjects.add(bird);

// Player references it
Object referencedBird = gameObjects.get(0);

// later in GameWorld,another scope,there is no access to the 'bird' object,trying to remove the bird from the world
Object objectToRemove = gameObjects.get(0);
gameObjects.remove(0);
objectToRemove = null;

// back in the Player class
Debug.log("is null " + (referencedBird == null)); // false! I need it to be true