垃圾收集器和Java中的四种类型的引用

Question

我正在与Java中的垃圾收集器作斗争。我想列出所有可从三个列表中的某个对象访问的对象，具体取决于引用类型：strong, soft, weak。那里没有幽灵。我知道我需要通过递归和反射来做，但我找不到一种简单的方法来实现它。请你帮助我好吗？这不是一个非常困难的问题，但我不知道如何以一种简单而正确的方式实现它。注意我不是要检测内存泄漏。

   public static List < Object > getStronglyReachable (Object from)
     // contains all objects that are ONLY strongly reachable

   public static List < Object > getSoftlyReachable (Object from)
     // contains all objects that are strongly OR softly reachable

   public static List < Object > getWeaklyReachable (Object from)
     // contains all objects that are strongly OR softly OR weakly reachable

这是我目前所拥有的，但它并没有真正起作用：

private static void collectAllReachableObjects (Object from, Set < Object > result) throws IllegalArgumentException, IllegalAccessException
{
    // if it's already added, don't do that again
    if (result.contains (from))
        return;

    // isStrongReference makes softAllowed false and weakAllowed false;
    // isSoftReference makes softAllowed true and weakAllowed false;
    // isWeakReference makes softAllowed true and weakAllowed true;
    // Phantom References are never allowed
    if (PhantomReference.class.isAssignableFrom (from.getClass ())) return;
    if (weakAllowed == false &&  WeakReference.class.isAssignableFrom (from.getClass ())) return;
    if (softAllowed == false &&  SoftReference.class.isAssignableFrom (from.getClass ())) return;

    // add to my list
    result.add (from);

    // if an object is an array, iterate over its elements
    if (from.getClass ().isArray ())
        for (int i = 0; i < Array.getLength (from); i++)
            collectAllReachableObjects (Array.get (from, i), result);

    Class < ? > c = from.getClass ();
    while (c != null)
    {
        Field fields[] = c.getDeclaredFields ();
        for (Field field : fields)
        {
            boolean wasAccessible = field.isAccessible ();
            field.setAccessible (true);
            Object value = field.get (from);
            if (value != null)
            {
                collectAllReachableObjects (value, result);
            }
            field.setAccessible (wasAccessible);
        }
        c = c.getSuperclass ();
    }
}