Operator Precedance

Just like boolean operators, +, -, *, /, and % have a defined precedence order.

The order of operations is the same as mathematics. Multiplication and division happen before addition and subtraction, with the modulo operator being a sort of "funky division." Parentheses can be used to control this order.

None of this should be a surprise if you learned PEMDAS in school.

// Following the order of operations:
// 2 * 3 + 3 * 9 / 2 - 2

// 2 * 3 happens first
// 6 + 3 * 9 / 2 - 2

// 3 * 9 happens next
// 6 + 27 / 2 - 2

// 27 / 2 happens next
// because of integer division, that gives 13 
// 6 + 13 - 2

// 6 + 13 comes next
// 19 - 2

// and the final result is 17;
int result = 2 * 3 + 3 * 9 / 2 - 2;
System.out.println(result);

The ==, !=, >, <, >=, and <= operators play a part here too¹. They all have a lower precedence order than all the math operators, so you can put them in the middle of any two math expressions.

// The == check happens last.
boolean areThingsSame = 3 * (4 - 1 + 3) * 4 == 5 * 3 + 1 * 3 * 9;