How do you decide what byte[] size to use for InputStream.read()?

Question

When reading from InputStreams, how do you decide what size to use for the byte[]?

int nRead;
byte[] data = new byte[16384]; // <-- this number is the o         


        

Answer 1

Most people use powers of 2 for the size. If the buffer is at least 512 bytes, it doesn't make much difference ( < 20% )

For network the optimal size can be 2 KB to 8 KB (The underlying packet size is typically up to ~1.5 KB) For disk access, the fastest size can be 8K to 64 KB. If you use 8K or 16K you won't have a problem.

Note for network downloads, you are likely to find you usually don't use the whole buffer. Wasting a few KB doesn't matter much for 99% of use cases.