Buffering

When using the java.io classes either directly or as a "native" file system under the extended file system, there is no attempt to buffer data explicitly unless the BufferedInputStream or BufferedOutputStream classes are used. Data is buffered implicitly by the underlying file system.

The NFS classes access the network directly through the Java Socket interface. To provide acceptable performance the NFS classes buffer all reads and writes. The buffer size varies from 8k for NFS version 2 servers to 32 for NFS version 3 servers though the actual buffer size is invisible to the Java application itself. The Java application must be diligent in calling the close() method when writing to an OutputStream or XRandomAccessFile to ensure that a partially filled buffer is written to the NFS server before the application exits. There is nothing in the Java Runtime that will cause partially written buffers to be flushed automatically at application exit.