This will consume additional transient disk usage: on Windows, attempts to delete or overwrite the files will result in an exception; on other platforms, which typically have a "delete on last close" semantics, while such operations will succeed, the bytes are still consuming space on disk. For many applications this limitation is not a problem (e.g. if you have plenty of disk space, and you don't rely on overwriting files on Windows) but it's still an important limitation to be aware of.
This class supplies the workaround mentioned in the bug report (disabled by default, see {@link #setUseUnmap}), which may fail on non-Sun JVMs. It forcefully unmaps the buffer on close by using an undocumented internal cleanup functionality. {@link #UNMAP_SUPPORTED} is true, if the workaroundcan be enabled (with no guarantees).
NOTE: Accessing this class either directly or indirectly from a thread while it's interrupted can close the underlying channel immediately if at the same time the thread is blocked on IO. The channel will remain closed and subsequent access to {@link MMapDirectory} will throw a {@link ClosedChannelException}.
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