Slicing byte arrays in Java

Question

I'm trying to slice a byte array to prune the first part of the array. I'm using ByteBuffer but it does not behave like I would expect.

byte[] myArray = new byte[10]; ByteBuffer buf = ByteBuffer.wrap(myArray); buf.position(5); ByteBuffer slicedBuf = buf.slice(); byte[] newArray = slicedBuf.array(); 

I would expect the size of newArray to be 5, containing only the last portion of my ByteBuffer. Instead, the full byte array is returned. I understand that this is because the "backing buffer" is the same all along.

How can I slice to have only the desired part of the array?

EDIT: Added context

The bytes are received from network. The buffer is formed like this :

[ SHA1 hash ] [ data... lots of it ]

I already have a function that takes a byte array as a parameter and calculate the SHA1 hash. What I want is to slice the full buffer to pass only the data without the expected hash.

Answer 1

You can use the Arrays.copyOfRange method. For example:

// slice from index 5 to index 9 byte[] slice = Arrays.copyOfRange(myArray, 5, 10);