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

i += ++i + i++ + ++i;

1. i=1 at start
2. i += X -> i = i + X -> i = 1 + X (so lets count X)
3. ++i will be incremented to 2 and return 2
4. i++ will return 2 and then be incremented to 3
5. ++i will be incremented from 3 to 4 and return 4
6. X = 2 + 2 + 4 = 8

So i = 1 + 8 -> i=9

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You would get 12 if your code would be something like this

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

because then your code would be i=1, and after calculating tmp i would be i=4, then i+=tmp -> i=4+8=12