Operator Precedence in Java Programming

What is Operator Precedence

Operator Precedence in Java programming is a rule that describe which operator is solved first in an expression. For example: * and / have same precedence and their associativity is Left to Right, so the expression 18 / 2 * 5 is treated as (18 / 2) * 5.

Video Explanation

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Let's take another example say x = 8 + 4 * 2; here value of x will be 16 and not 24 why, because * operator has a higher precedence than + operator. So 4*2 gets multiplied first and then adds into 8.

Operator Associativity means how operators of the same precedence are evaluated in an expression. Associativity can be either from left to right or right to left.

Basic Operator Precedence

When solving arithmetic equations, follow this order:

If brackets are there in an equation then it will be solved first.

Example:
  (2 + 3) * 4 -> first do 2 + 3 -> then multiply.

These are equal in priority. Solve from left to right as they appear in an equation.

Example:
   12 / 2 * 3
   -> First do 12 / 2 = 6
   -> Then 6 * 3 = 18

Do not do multiplication before division or vice versa — just go left to right.

These also have equal priority. Solve from left to right as they appear in an equation.

Example:
   10 − 3 + 2
   -> First do 10 − 3 = 7
   -> Then 7 + 2 = 9

Now let's see some examples for more understanding.

int x = 45 % 2 + 3 * 2;   // result of x is 7

45 % 2 + 3 * 2
45 % 2 + 3 * 2   will be solved as per operator precedence rule
1 + 3 * 2    will be solved as per operator precedence rule
1 + 6    will be solved as per operator precedence rule
7 (Answer)

int x = 19 + (5 / 2) + 4 % 2 - 6 * 3;   // result of x is 3

19 + (5 / 2) + 4 % 2 - 6 * 3
19 + (5 / 2) + 4 % 2 - 6 * 3     will be solved as per operator precedence rule
19 + 2 + 4 % 2 - 6 * 3     will be solved as per operator precedence rule
19 + 2 + 0 - 6 * 3     will be solved as per operator precedence rule
19 + 2 + 0 - 18     will be solved as per operator precedence rule
21 + 0 - 18     will be solved as per operator precedence rule
21 - 18     will be solved as per operator precedence rule
3 (Answer)

List of Operator Precedence in Java

The table below shows all the operators in Java with precedence and associativity.