Buffer Size for BufferedInputStream

Question

How to determine the size of Buffer, while using Buffered Input Stream for reading batch of files? Is it based on the File size?I'm using,

byte[] buf = new byte[4096];

If i increase the buffer size,it will read quickly?

Answer 1

The default, which is deliberately undocumented, is 8192 bytes. Unless you have a compelling reason to change it, don't change it.

Answer 2

You can easily test it yourself, but it's not really a big issue. A few kilobytes is enough for the buffer, so you'll get good reading speeds.

If you profile your application and do realize that File IO is a performance bottleneck, there are ways to make it quicker, such as memorymapping a file.