Java Operators Explained: Types, Precedence, and Use-Cases

Operators in Java are symbols used to perform operations on variables and values. Whether you're doing arithmetic, comparing values, or writing conditions, operators are fundamental to Java programming.

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🔍 What Is an Operator?

An operator is a symbol that tells the compiler to perform specific mathematical or logical operations.
Example:

int c = a + b;  // '+' is an operator

📦 What Is an Operand?

Operands are the values or variables on which operators work.
In the expression A + B = C, A, B, and C are operands.

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🧱 Operator Classification

Java categorizes operators into three arity types:

• Unary – requires one operand (++a)
• Binary – requires two operands (a + b)
• Ternary – requires three operands (condition ? val1 : val2)

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🔢 Types of Operators in Java

1. Arithmetic Operators

Used to perform basic mathematical operations.

Unary Operators

Operator	Description	Example
++	Increment	a++ is a = a + 1
--	Decrement	a-- is a = a - 1
!	Logical NOT	!true becomes false

Binary Operators

Operator	Description
+	Addition / String Concatenation
-	Subtraction
*	Multiplication
/	Division
%	Modulus (Remainder)

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2. Assignment Operators

Assign values to variables and combine assignment with other operations.

Operator	Meaning	Example
=	Simple Assignment	a = 5
+=	Addition + Assignment	a += 3 → a = a + 3
-=	Subtraction + Assignment	a -= 2
*=	Multiplication + Assignment	a *= 2
/=	Division + Assignment	a /= 4
%=	Modulus + Assignment	a %= 2
<<=, >>=, &=, ^=, |=	Bitwise assignment combos	a |= 2

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3. Relational Operators

Used to compare two values.

Operator	Meaning	Example
==	Equal to	a == b
!=	Not equal	a != b
>	Greater than	a > b
<	Less than	a < b
>=	Greater than or equal to	a >= b
<=	Less than or equal to	a <= b

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4. Logical Operators

Combine multiple conditions.

Operator	Name	Example
&&	Logical AND	(a > 0 && b > 0)
||	Logical OR	(a > 0 || b > 0)
!	Logical NOT	!(a > b)

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5. Bitwise Operators

Operate at the binary level.

Operator	Description	Example
&	AND	a & b
|	OR	a | b
^	XOR	a ^ b
~	Bitwise NOT	~a
<<	Left shift	a << 2
>>	Right shift	a >> 2
>>>	Zero-fill right shift	a >>> 2

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6. instanceof Operator

Used to test if an object is an instance of a class or interface.

if (obj instanceof String) { ... }

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7. Conditional (Ternary) Operator

Short form of an if-else condition:

int result = (a > b) ? a : b;

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🧮 Operator Precedence and Associativity

Operator precedence determines the order of execution in expressions.

Precedence	Operators	Associativity
15	() [] .	Left to Right
14	++ -- (postfix)	Left to Right
13	++ -- + - ! ~	Right to Left
12	* / %	Left to Right
11	+ -	Left to Right
10	<< >> >>>	Left to Right
9	< <= > >= instanceof	Left to Right
8	== !=	Left to Right
7	&	Left to Right
6	^	Left to Right
5	|	Left to Right
4	&&	Left to Right
3	||	Left to Right
2	? :	Right to Left
1	= += -= etc.	Right to Left

Tip: Use parentheses () to clarify precedence in complex expressions.

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🛠️ Real-World Example

double bill = 400;
double discount = (bill > 300) ? 0.10 : 0.05;
bill = bill - (bill * discount);

Use ternary instead of if-else for short decisions.

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🧠 Interview Perspective

• What's the difference between == and .equals()?
• How does short-circuit evaluation work with && and ||?
• Explain instanceof in polymorphism context.

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🧭 Java Version Relevance

Feature	Version	Notes
instanceof operator	Java 1.0	Originally added
instanceof pattern matching	Java 16	if (x instanceof String s) — no cast needed
Ternary operator	Java 1.0	Always supported
Precedence rules	Java 1.0	Core part of the language

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✅ Summary

• Java provides a rich set of operators: arithmetic, assignment, relational, logical, bitwise, ternary, and more.
• Understanding precedence avoids bugs in complex expressions.
• Most operators follow mathematical logic but behave slightly differently in short-circuiting and bitwise contexts.

Mastering operators is the foundation for writing correct and optimized Java code.