Just a simple trick question to see if guys are on their toes

public class Test {
public static void main(String[] args) {
int n = 0;
for (int m = 0; m < 5; m++) {
n = n++;
System.out.println(n);
}
}
}
Output:
0
0
0
0
0
Why?
Who will be first to answer correctly?
--
Regards
Brian Ngure