[Solved] java programming unary operator precedence

a++ means that a is incremented after evaluation

++a means that a is incremented before evaluation

a is incremented three times in total, so its value is 3 after the expression is computed.

b= a++ + ++a * ++a; means that a is evaluated (0), then incremented, this (0) is added to the result of ++a * ++a, which means that the left part is 2 (because a, which is 1 from before, is incremented before evaluation, thus is evaluated as 2), and the right part is 3 (a was 2, and is incremented before evaluation, so it evaluated as 3). Thus the result of the expression is 2 * 3 = 6.

To explain these incrementations a bit better:

x = ++a; is like a = a + 1; x = a;

x = a++; is like x = a; a = a + 1;