While loop output.

Question

What is the output of this code?
byte by = 0;
while(by > 0)
by++;
System.out.println(by);

Why is it equal to -128?

Answer 1

Because of the limits of the type byte: between -128 and 127. The last step when variable by is positive is 127, after incrementing it becomes -128 and the loop stops.

Answer 2

The output of your code ist 0. But if you modify the while condition to (by >= 0), it is -128.