How to use java CRC32 class

Question

I am trying to use the CRC32 class from Java. The input of the data is a byte array which represent an Ethernet packet (Eth + IP + payload). However the output of the checksum from CRC32 class is different from the one shows up on wireshark.

Can anyone tell me if the CRC calculation of CRC32 class is same as the standard ethernet II checksum calculation?

Answer 1

Yes, it's the same CRC, which means it should be the same 32 bits. However those bits might not be ending up where you're expecting. Try reversing the bytes, reversing the bits, and reversing both to see if you get a match.