Weak, soft, and phantom references can improve the memory characteristics of your application by allowing flexible caching.

弱引用、软引用和虚引用允许灵活的缓存，能够改进应用程序的内存特性。

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It was thus that the phantom which had been called M. Madeleine vanished from M. sur M. Only three or four persons in all the town remained faithful to his memory.

这个一度称为马德兰先生的幽灵便这样在滨海蒙特勒伊消逝了。全城中，只有三四个人还追念他。

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Furthermore, an object in memory can be referenced by multiple references that could be strong, soft, weak, or phantom. Before proceeding further, let's look at some terminology.

而且，内存中的一个对象可以被多个引用(可以是强引用、软引用、弱引用或虚引用)引用。

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