Assigning int to byte in java?

Question

int val = 233;
byte b = (byte) val;
System.out.println(b);

I have a simple case: I have one integer with some value & I want to convert that value into a byte for output. But in this case, a negative value is coming.

How can I successfully place the int value to byte type?

Answer 1

In Java byte range is -128 to 127. You cannot possibly store the integer 233 in a byte without overflowing.

Answer 2

Java's byte is a signed 8-bit numeric type whose range is -128 to 127 (JLS 4.2.1). 233 is outside of this range; the same bit pattern represents -23 instead.

11101001 = 1 + 8 + 32 + 64 + 128 = 233 (int)
           1 + 8 + 32 + 64 - 128 = -23 (byte)

That said, if you insist on storing the first 8 bits of an int in a byte, then byteVariable = (byte) intVariable does it. If you need to cast this back to int, you have to mask any possible sign extension (that is, intVariable = byteVariable & 0xFF;).