Caching

The NFS client uses the same cache model as other NFS client implementations. File data and attributes are cached for a time interval depending on the frequency of update. If the file is updated frequently then the cache time will be as short as 3 seconds. However if the file is updated infrequently then the cache time may be as long as 60 seconds. If the file changes on the server during the time in which the cached copy is considered valid, then the change will not be noticed until the cache time has expired. This caching behavior should be considered when Java applications running in different Java virtual machines or on multiple network clients need to coordinate their activity around a common set of files.

The NFS client caches aggressively for good network performance. Currently the cache is open-ended: as new NFS files or directories are encountered, their filehandles and file attributes are cached. These cache entries are never released, so if a Java application touches a large number of files perhaps in a file tree walk, then the application may encounter an OutOfMemoryError. A future version of the client will manage the cache within a bounded amount of memory.