Pre- and postincrement in Java

Question

I just wanted to create a little Java-Puzzle, but I puzzled myself. One part of the puzzle is:

What does the following piece of code do:

Answer 1

The code

int i = 1;
i += ++i + i++ + ++i

is equivalent to

int tmp1 = i // 1, +=

i ++; // 2
int tmp2 = i; // 2

int tmp3 = i; // 2
i ++; // 3

i ++; // 4
int tmp4 = i; // 4

i = tmp1 + tmp2 + tmp3 + tmp4; // 9