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; is the same as i = i + ++i + i++ + ++i;

The right-hand side is calculated from left-to-right, yielding i = 1 + 2 + 2 + 4; (which yields i = 9).