converting an array of signed bytes to unsigned bytes [duplicate]

Question

I have a array of bytes.

bytes[] = [43, 0, 0, -13, 114, -75, -2, 2, 20, 0, 0]

I want to convert it to unsigned bytes in Java. this is what I did: created a new array and copy the values with & 0xFF:

    this.bytes = new byte[bytes.length];
    for (int i=0;i<bytes.length;i++)
        this.bytes[i] = (byte) (bytes[i] & 0xFF);

but the values stay negative in the new array as well. what am I doing wrong?

Answer 1

bytes in Java are always signed.

If you want to obtained the unsigned value of these bytes, you can store them in an int array:

byte[] signed = {43, 0, 0, -13, 114, -75, -2, 2, 20, 0, 0};
int[] unsigned = new int[signed.length];
for (int i = 0; i < signed.length; i++) {
    unsigned[i] = signed[i] & 0xFF;
}

You'll get the following values:

[43, 0, 0, 243, 114, 181, 254, 2, 20, 0, 0]

Answer 2

Java has no thing called an unsigned byte. You have to use other types like short or int to be able to hold values > 127.