In java.io package, BufferedInputStream uses a default buffer size of 2048 bytes, and BufferedOutputStream uses a default buffer size of 512 bytes. These buffer sizes are too small and they cause significant performance penalty to the system because of the extra reads and writes. The small buffer size also causes significant performance bottleneck in socket read/write on high speed network. This bug is on all platforms.
Most OSes that we support uses a buffer size of 8192 (8K) bytes for their IO buffering, and this is also the buffer size used by customer VM on Win32. We should change the default buffer size in these two classes to 8K.