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Rajesh Bhola
Rajesh Bhola

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Java Operator Precedence

#beginners #interview #java #programming

When an expression contains multiple operators, how does Java decide which operation to perform first?

The answer lies in operator precedence and associativity.

These concepts are frequently tested in Java interviews because they help determine how complex expressions are evaluated.

In this guide, you'll learn:

  • What operator precedence is
  • Complete precedence table
  • Associativity rules
  • Operand evaluation order
  • Parentheses and precedence
  • Common interview questions and tricky examples

What is Operator Precedence?

Operator precedence determines which operator is evaluated first when an expression contains multiple operators.

Higher-precedence operators are evaluated before lower-precedence operators unless parentheses change the order.

Complete Java Operator Precedence Table

Level Operator Type Operators Associativity Notes / Edge Cases
1 Unary / Creation ++, --, ~, !, new, cast Right-to-Left Prefix ++/-- and casts evaluate right-to-left.
2 Multiplicative *, /, % Left-to-Right Higher priority than addition/subtraction.
3 Additive +, - Left-to-Right Controls basic math and string concatenation.
4 Shift <<, >>, >>> Left-to-Right >>> is the unsigned (zero-fill) right shift.
5 Relational / Comparison <, <=, >, >=, instanceof Left-to-Right Used for structural bounds checking.
6 Equality ==, != Left-to-Right Compares primitives by value, objects by memory address.
7 Bitwise AND & Left-to-Right Evaluates both sides completely (no short-circuit).
8 Bitwise XOR ^ Left-to-Right Strict exclusive OR.
9 Bitwise OR | Left-to-Right The | requires a backslash escape inside markdown tables.
10 Short-circuit AND && Left-to-Right Skips RHS if LHS evaluates to false.
11 Short-circuit OR || Left-to-Right Skips RHS if LHS evaluates to true.
12 Ternary / Conditional ? : Right-to-Left The only three-operand operator in Java.
13 Assignment =, +=, -=, *=, etc. Right-to-Left Always happens dead last in an expression.

Tip: Many simplified charts combine multiplicative and additive operators into one "Arithmetic" category, but Java's actual precedence gives *, /, % higher precedence than + and -.

Arithmetic Precedence

Within arithmetic operators:

Higher precedence

*   /   %
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Lower precedence

+   -
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Example 

int x = 2 + 3 * 4;
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Evaluation

3 * 4 = 12

↓

2 + 12

↓

14
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Output

14
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Another Example 

int x = 10 + 20 / 5 - 2 * 3;
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Evaluation

20 / 5 = 4

2 * 3 = 6

10 + 4 - 6

↓

8
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Output

8
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Mixed Operators

Arithmetic Before Comparison 

int x = 10;

boolean result = x + 5 > 12;
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Evaluation

10 + 5 = 15

↓

15 > 12

↓

true
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Comparison Before Logical 

boolean result = 5 > 3 && 7 < 10;
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Evaluation

5 > 3

↓

true

7 < 10

↓

true

true && true

↓

true
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Unary Operators Have Higher Precedence 

int x = 5;

int y = -x + 3;
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Evaluation

-x

↓

-5

↓

-5 + 3

↓

-2
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Output

-2
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Operator Precedence vs Operand Evaluation

These are different concepts.

Many beginners confuse them.

Operator Precedence

Determines which operator executes first.

Operand Evaluation

Determines which operand is evaluated first.

Java Rule

Operands are always evaluated from left to right.

Only after all operands are evaluated does Java apply operator precedence.

Famous Interview Example 

public class Test {

    public static void main(String[] args) {

        System.out.println(
                m1(1)
                + m1(2) * m1(3) / m1(4) * m1(5)
                + m1(6)
        );
    }

    static int m1(int i) {
        System.out.println(i);
        return i;
    }
}
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Output 

1
2
3
4
5
6
12
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Notice:

The numbers 1 through 6 are printed in order.

This proves Java evaluates operands left to right.

Step 1: Operand Evaluation

Java first evaluates

m1(1)

↓

m1(2)

↓

m1(3)

↓

m1(4)

↓

m1(5)

↓

m1(6)
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Each method call prints its number.

Step 2: Apply Operator Precedence

The expression becomes

1 + 2 * 3 / 4 * 5 + 6
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Now apply precedence.

2 * 3

↓

6

6 / 4

↓

1

1 * 5

↓

5

1 + 5 + 6

↓

12
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Final output

12
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Operands First, Operators Later

Think of Java as doing two phases.

Phase 1

Evaluate operands

↓

Left to Right
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Phase 2

Apply operators

↓

According to precedence
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Associativity

What if two operators have the same precedence?

Associativity determines the order.

Left-to-Right Associativity

Most Java operators are left associative.

Example

20 / 5 * 2
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Evaluation

20 / 5

↓

4

4 * 2

↓

8
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Right-to-Left Associativity

Assignment operators are right associative.

Example

int a;
int b;
int c;

a = b = c = 10;
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Equivalent to

a = (b = (c = 10));
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Evaluation

c = 10

↓

b = 10

↓

a = 10
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Conditional Operator Associativity

The conditional operator is also right associative.

Example

condition1
? value1
: condition2
    ? value2
    : value3;
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This is interpreted as

condition1

?

value1

:

(condition2 ? value2 : value3)
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Parentheses Override Precedence

Parentheses always execute first.

Without parentheses

int x = 2 + 3 * 4;
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Output

14
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With parentheses

int y = (2 + 3) * 4;
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Evaluation

2 + 3

↓

5

5 * 4

↓

20
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Output

20
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Practical Examples

Example 1 

10 + 5 == 15
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Evaluation

10 + 5

↓

15

15 == 15

↓

true
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Example 2 

5 > 3 && 2 < 1
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Evaluation

true && false

↓

false
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Example 3 

int a;
int b;

a = b = 5;
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Result

a = 5

b = 5
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A Note About Expressions Like ++x + x++

Expressions that modify the same variable multiple times in one statement can be confusing.

Although Java defines a left-to-right operand evaluation order, such expressions reduce readability and are discouraged in production code.

For interviews, evaluate them carefully by applying Java's operand evaluation order and the semantics of pre/post increment.

Interview Questions

What is operator precedence?

It determines which operator is evaluated first in an expression.

Which operators have the highest precedence?

Postfix and unary operators.

Which operators have the lowest precedence?

Assignment operators.

What evaluates first: operands or operators?

Operands.

Java evaluates operands from left to right before applying operator precedence.

What decides the order when two operators have the same precedence?

Associativity.

Which operators are right associative?

  • Assignment operators
  • Conditional (?:)
  • Prefix unary operators

How do you override precedence?

Using parentheses.

Memory Tricks 🧠

Easy Rule 

Operands

↓

Left to Right

Operators

↓

By Precedence
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Highest to Lowest 

PRECEDENCE (high to low):
1. () [] . ++ -- (postfix)
2. ++ -- + - ~ ! (prefix/unary)
3. * / %
4. + -
5. << >> >>>
6. < > <= >= instanceof
7. == !=
8. &
9. ^
10. |
11. &&
12. ||
13. ? :
14. = += -= *= /= %= etc.
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Remember

Parentheses beat everything.

Key Takeaways

  • Operator precedence determines the order in which operators are evaluated in an expression.
  • Java first evaluates operands from left to right, then applies operators according to precedence.
  • Multiplication, division, and modulo have higher precedence than addition and subtraction.
  • When operators have the same precedence, associativity determines the evaluation order.
  • Most operators are left-associative, while assignment (=) and the conditional operator (?:) are right-associative.
  • Parentheses always override the default precedence rules and improve code readability.
  • Understanding precedence and associativity helps avoid bugs and is a common Java interview topic.

If you found this guide helpful, leave a ❤️ and follow for more beginner-friendly Java tutorials, interview questions, and practical coding examples.

Happy Coding!

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