Different CRC32 values in Java and swift - swift

Question

I'm in the process of writing a utility in Swift which can be used to calculate CRC32 checksum of an input data . A similar utility exists in Java which we are using extensively and has been working well for us.
The Java Utility uses java.util.zip.CRC32 to calculate the checksum. Pseudo code is as follows :
Java code:
private void transferFileData(short index, byte[] data, long dataSize) {
CRC32 crc32 = new CRC32();
long crc = crc32.update(data, (int) dataSize);
System.out.println("CRC32 : " + crc);
}
The Swift uses the CRC32 (import CryptoSwift) CryptoSwift code for generating the checksum in swift is as follows :
Swift code:
func crc32Func(_ item:[Int8] ) {
let data = Data(bytes: item, count: item.count)
let byte = data.bytes
let crc32 = byte.crc32()
print("checksum == \(crc32)"
}
The output from the Java code is :
Checksum in Java : 3771181957
The output from the swift code is :
Checksum in swift : 1894162356
Why the checksum values are not the same?
This is the code applied by Swift as below:
The data type is [Int8]
The data size is 450 bytes.
let item:
[Int8] = [45, 35, 76, 70, 67, 68, 95, 70, 79, 84, 65, 95, 70, 87, 95,
70, 85, 76, 76, 10, 80, 75, 71, 95, 86 , 69, 82, 83, 73, 79, 78, 58,
51, 46, 48, 46, 48, 10, 66, 65, 83, 69, 95, 86, 69, 82, 83, 73, 79, 78
, 58, 10, 72, 65, 83, 72, 58, 51, 97, 57, 98, 51, 99, 52, 56, 57, 52,
56, 56, 53, 49, 50, 53, 52, 55 , 48, 51, 49, 54, 48, 57, 56, 48, 101,
98, 101, 51, 54, 54, 10, 80, 75, 71, 95, 83, 73, 90, 69, 58, 49 , 51,
49, 48, 55, 50, 48, 10, 26, 0, 0, 5, 32, -79, 11, 5, 8, -39, -5, 4, 8,
-35, -5, 4, 8, -15, -5, 4, 8, -13, -5, 4, 8, -11, -5, 4, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -31, -15, 10, 8, -9, -5, 4, 8,
0, 0, 0, 0, -127, -14, 10, 8, -27, -14, 10, 8, 1, 12, 5, 8, 1, 12, 5,
8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1,
12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12,
5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8,
-7, -5, 4, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 9, -4,
4, 8, 25, -4, 4, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5,
8, 1, 12, 5, 8, 57, -4, 4, 8, 1, 12, 5, 8, 73, -4, 4, 8, 89, -4, 4, 8,
105, -4, 4, 8, 1, 12, 5, 8, -39, -4, 4, 8, 1, 12, 5, 8, 1, 12, 5, 8,
1, 12, 5, 8, 41, -4, 4, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1,
12, 5 , 8, 1, 12, 5, 8, 1, 12, 5, 8, 121, -4, 4, 8, -119, -4, 4, 8, 1,
12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12,
5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8,
1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, 1, 12, 5, 8, -103, -4]
is input.
Java input:
byte[] data
The type is long and the data entered is the same as [Int8] of swift data.

Answer 1

The CRC you are getting from your Swift code (whatever that actual code is) is correct. The CRC you are getting from your Java code (whatever that actual code is) is not correct.
There is no way to know what you're doing wrong in your Java code without at least being able to see that code.