Java Operators

Learn about available Java operators, precedence order and understand their usages with example. We will also try to understand when to use which operator and what to expect in result.

Table of Contents

1. What Is an Operator?
2. Assignment Operator (=)
3. Arithmetic Operators
    3.1. Unary Arithmetic Operators
    3.2. Binary Arithmetic Operators
4. String Concatenation Operator (+)
5. Relational Operators
6. Boolean Logical Operators
7. Bitwise Operators
8. Ternary Operator
9. Java Operator Precedence Table

1. What Is an Operator?

An operator is a symbol that performs a specific kind of operation on one, two, or three operands, and produces a result. The type of the operator and its operands determines the kind of operation performed on the operands and the type of the result produced.

1.1. Classification of Java Operators

Operators in Java can be categorized based on two criteria:

  • Number of operands – There are three types of operators based on the number of operands. An operator is called a unary, binary, or ternary operator based on the number of operands. If an operator takes one operand, it called a unary operator; if it takes two operands, it called a binary operator; if it takes three operands, it called a ternary operator.
  • Type of operation they perform – An operator is called an arithmetic operator, a relational operator, a logical operator, or a bitwise operator, depending on the kind of operation it performs on its operands.

2. Assignment Operator (=)

  • An assignment operator (=) is used to assign a value to a variable.
  • It is a binary operator. It takes two operands.
  • The value of the right-hand operand is assigned to the left-hand operand.
  • The left-hand operand must be a variable.
//26 is the right-hand operand. 
//counter is the left-hand operand, which is a variable of type int.

int counter = 26; 

Java ensures that the value of the right-hand operand of the assignment operator is assignment compatible to the data type of the left-hand operand. Otherwise, a compile-time error occurs. In case of reference variables, you may be able to compile the source code and get a runtime ClassCastException error if the object represented by the right-hand operand is not assignment compatible to the reference variable as the left-hand operand.

3. Arithmetic Operators

  • Operators like (+ (plus), (minus), * (multiply), / (divide)) are called arithmetic operators in Java.
  • It can only be used with numeric type operands. It means, both operands to arithmetic operators must be one of types byte, short, char, int, long, float, and double.
  • These operators cannot have operands of boolean primitive type and reference type.
int sum = 10 + 20; 

int difference = 50 - 20; 

long area = 20l * 30l;    

int percentage = 20 / 100;

3.1. Unary Arithmetic Operators

OperatorDescription
'+'Unary plus operator; indicates positive value (numbers are positive without this, however)
'-'Unary minus operator; negates an expression value
'++'Increment operator; increments a value by 1
'--'Decrement operator; decrements a value by 1
'!'Logical complement operator; inverts the value of a boolean

3.2. Binary Arithmetic Operators

OperatorDescription
'+'Addition – Adds values on either side of the operator
'-'Subtraction – Subtracts right hand operand from left hand operand
'*'Multiplication – Multiplies values on either side of the operator
'/'Division – Divides left hand operand by right hand operand
'%'Modulus – Divides left hand operand by right hand operand and returns remainder

4. String Concatenation Operator (+)

The '+' operator is overloaded in Java. An operator is said to be overloaded operator if it is used to perform more than one function.

4.1. Concatenate two strings

So far, you have seen its use as an arithmetic addition operator to add two numbers. It can also be used to concatenate two strings.

String str1 = "Hello";
String str2 = " World";

String str3 = str1 + str2;      // Assigns "Hello World" to str3

3.2. Concatenate primitive to string

The string concatenation operator is also used to concatenate a primitive and a reference data type value to a string.

int num = 26;

String str1 = "Alphabets";

String str2 = num + str1;    // Assigns "26Alphabets" to str2

4.2. Concatenate null

If a reference variable contains the ‘null’ reference, the concatenation operator uses a string “null”.

String str1 = "I am ";

String str2 = null;

String str3 = str1 + str2;    // Assigns "I am null" to str3

5. Relational Operators

  • All relational operators are binary operators.
  • They take two operands.
  • The result produced by a relational operator is always a Boolean value true or false.
  • They are mostly used in Java control statements such as if statements, while statements etc.

Let’s see below all available relational operators in java.

OperatorDescription
'=='Equals to – Checks if the values of two operands are equal or not, if yes then condition becomes true.
'!='Not equals to – Checks if the values of two operands are equal or not, if values are not equal then condition becomes true.
'>'Greater than – Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true.
'<'Less than – Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true.
'>='Greater than or equals to – Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true.
'<='Less than or equals to – Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true.
int result = 20; 
        
if( result > 10) {                  //true
    //some operation
}

boolean isEqual = ( 10 == 20 );     //false

6. Boolean Logical Operators

  • All Boolean logical operators can be used only with boolean operand(s).
  • They are mostly used in control statements to compare two (or more) conditions.
OperatorDescription
'!'returns true if the operand is false, and false if the operand is true.
'&&'returns true if both operands are true. If either operand is false, it returns false.
'&'returns true if both operands are true. If either operand is false, it returns false.
'||'returns true if either operand is true. If both operands are false, it returns false.
'|'returns true if either operand is true. If both operands are false, it returns false.
'^'it returns true if one of the operands is true, but not both. If both operands are the same, it returns false.
'&=;'if both operands evaluate to true, &= returns true. Otherwise, it returns false.
'|='if either operand evaluates to true, != returns true. Otherwise, it returns false.
'^='if both operands evaluate to different values, that is, one of the operands is true but not both, ^= returns true. Otherwise, it returns false.
int result = 20; 
        
if( result > 10 && result < 30) {      
    //some operation
}

if( result > 10 || result < 30) {      
    //some operation
}
  1. The logical AND operator (&) works the same way as the logical short-circuit AND operator (&&), except for one difference. The logical AND operator (&) evaluates its right-hand operand even if its left-hand operand evaluates to false.
  2. The logical OR operator works the same way as the logical short-circuit OR operator, except for one difference. The logical OR operator evaluates its right-hand operand even if its left-hand operand evaluates to true.

7. Bitwise Operators

A bitwise operator manipulates individual bits of its operands. Java defines several bitwise operators, which can be applied to the integer types, long, int, short, char, and byte.

OperatorDescription
'&'Binary AND Operator copies a bit to the result if it exists in both operands.
'|'Binary OR Operator copies a bit if it exists in either operand.
'^'Binary XOR Operator copies the bit if it is set in one operand but not both.
'~'Binary Ones Complement Operator is unary and has the effect of ‘flipping’ bits.
<<Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand.
>>Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand.
>>>Shift right zero fill operator. The left operands value is moved right by the number of bits specified by the right operand and shifted values are filled up with zeros.

8. Ternary Operator

  • Java has one conditional operator. It is called a ternary operator as it takes three operands.
  • The two symbols of “?” and “:” make the ternary operator.
  • If the boolean-expression evaluates to true, it evaluates the true-expression; otherwise, it evaluates false-expression.

8.1. Syntax

boolean-expression ? true-expression : false-expression

8.2. Ternary Operator Example

int number1 = 40;
int number2 = 20;

int biggerNumber = (number1 > number2) ? number1 : number2;

//Compares both numbers and return which one is bigger

9. Java Operator Precedence Table

Java has well-defined rules for specifying the order in which the operators in an expression are evaluated when the expression has several operators. For example, multiplication and division have higher precedence than addition and subtraction.

Precedence rules can be overridden by explicit parentheses.

When two operators share an operand the operator with the higher precedence goes first. For example, 1 + 2 * 3 is treated as 1 + (2 * 3) because precedence of multiplication is higher than addition.

In above expression, if you want to add values first then use explicit parentheses like this – (1 + 2) * 3.

PrecedenceOperatorTypeAssociativity
15()
[]
·
Parentheses
Array subscript
Member selection
Left to Right

14++
Unary post-increment
Unary post-decrement
Right to left
13++

+

!
~
( type )
Unary pre-increment
Unary pre-decrement
Unary plus
Unary minus
Unary logical negation
Unary bitwise complement
Unary type cast
Right to left
12 *
/
%
Multiplication
Division
Modulus
Left to right
11+
Addition
Subtraction
Left to right
10<<
>>
>>>
Bitwise left shift
Bitwise right shift with sign extension
Bitwise right shift with zero extension
Left to right
9<
<=
>
>=
instanceof
Relational less than
Relational less than or equal
Relational greater than
Relational greater than or equal
Type comparison (objects only)
Left to right
8==
!=
Relational is equal to
Relational is not equal to
Left to right
7&Bitwise ANDLeft to right
6^Bitwise exclusive ORLeft to right
5|Bitwise inclusive ORLeft to right
4&&Logical AND

Left to right
3||Logical ORLeft to right
2? :Ternary conditionalRight to left
1=
+=
-=
*=
/=
%=
Assignment
Addition assignment
Subtraction assignment
Multiplication assignment
Division assignment
Modulus assignment
Right to left

That’s all for the operators in java.

Happy Learning !!

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