Java 中软引用的用例是什么？
Java 中软引用的用例是什么？当 JVM 内存不足时，对非关键项目进行垃圾收集是否有用，以便在关闭 JVM 之前释放足够的资源来转储关键信息？
它们被称为软引用吗，因为它们很软，并且在“承受压力”时会中断，即：JVM 内存不足。我了解弱引用和幻象引用，但在需要这些时却不太了解。
What is a use case for a soft reference in Java? Would it be useful to garbage collect non-critical items when a JVM has run out of memory in order to free up enough resources to perhaps dump critical information before shutting down the JVM?
Are they called soft-references in they they are soft and break when "put under stress" ie:the JVM has run out of memory. I understand weak references and phantom references but not really when these would be needed.
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一种用途是缓存。想象一下，您想要维护大型对象的内存缓存，但不希望该缓存消耗可用于其他目的的内存（因为缓存始终可以重建）。通过维护对对象的软引用的缓存，JVM 可以释放引用的对象，并将它们占用的内存重新用于其他目的。缓存只需要在遇到损坏的软引用时清除它们即可。
另一种用途可能是在内存有限的设备（例如移动电话）上维护应用程序映像。当用户打开应用程序时，先前的应用程序映像可以保留为软引用，以便在需要内存用于其他用途时可以将其清除，但如果不需要内存，则它们仍然存在。如果内存没有压力，这将允许用户更快地返回到应用程序，并且如果需要执行其他操作，则允许回收前一个应用程序的内存。
One use is for caching. Imagine you want to maintain an in-memory cache of large objects but you don't want that cache to consume memory that could be used for other purposes (for the cache can always be rebuilt). By maintaining a cache of soft-references to the objects, the referenced objects can be freed by the JVM and the memory they occupied reused for other purposes. The cache would merely need to clear out broken soft-references when it encounters them.
Another use may be for maintaining application images on a memory-constrained device, such as a mobile phone. As the user opens applications, the previous application images could be maintained as soft-references so that they can be cleared out if the memory is needed for something else but will still be there if there is not demand for memory. This will allow the user to return to the application more quickly if there is no pressure on memory and allow the previous application's memory to be reclaimed if it is needed for something else.
这个文章让我对它们中的每一个都有了很好的理解（弱引用、软引用和幻像引用）。以下是总结的引用：
This article gave me a good understanding of each of them (weak, soft and phantom references). Here's a summarized cite:
我能想到的最好的例子就是缓存。如果内存出现问题，您可能不介意转储缓存中最旧的条目。缓存大型对象图也可能使这种情况成为可能。
The best example I can think of is a cache. You might not mind dumping the oldest entries in the cache if memory became a problem. Caching large object graphs might make this likely as well.
有关如何将 SoftReference 用作缓存的示例，请参见 发布。
An example of how a SoftReference can be used as a cache can be found in this post.