Java Operators

Ankit Mishra July 19, 2019

Java Operators

In this article, you'll learn everything about different types of operators in Java programming language, their syntax and how to use them with examples.

Operators are special symbols (characters) that carry out operations on operands (variables and values). For example, + is an operator that performs addition.
In Java variables article, you learned to declare variables and assign values to variables. Now, you will learn to use operators to manipulate variables.

Assignment Operators

Assignment operators are used in Java to assign values to variables. For example, 
        
int age;
age = 5;
The assignment operator assigns the value on its right to the variable on its left. Here, 5 is assigned to the variable age using = operator. There are other assignment operators too. However, to keep things simple, we will learn other assignment operators later in this article.
Example 1: Arithmetic Operators 
        
class AssignmentOperator {
    public static void main(String[] args) {
     
     int number1, number2;
     
     // Assigning 5 to number1 
     number1 = 5;
     System.out.println(number1);
          
     // Assigning value of variable number2 to number1
     number2 = number1;
     System.out.println(number2);
    }
}
When you run the program, the output will be: 
5
5

Arithmetic Operators

Arithmetic operators are used to perform mathematical operations like addition, subtraction, multiplication, devide etc.
Operator Meaning
+ Addition (also used for string concatenation)
- Subtraction Operator
* Multiplication Operator
÷ Division Operator
% Remainder Operator

Example 2: Arithmetic Operator 

class ArithmeticOperator {
    public static void main(String[] args) {
     
     double number1 = 12.5, number2 = 3.5, result;
     
     // Using addition operator
     result = number1 + number2;
     System.out.println("number1 + number2 = " + result);
     
     // Using subtraction operator
     result = number1 - number2;
     System.out.println("number1 - number2 = " + result);
     
     // Using multiplication operator
     result = number1 * number2;
     System.out.println("number1 * number2 = " + result);
     // Using division operator
     result = number1 / number2;
     System.out.println("number1 / number2 = " + result);
     
     // Using remainder operator
     result = number1 % number2;
     System.out.println("number1 % number2 = " + result);
    }
}
When you run the program, the output will be: 
number1 + number2 = 16.0
number1 - number2 = 9.0
number1 * number2 = 43.75
number1 / number2 = 3.5714285714285716
number1 % number2 = 2.0
In above example, all operands used are variables. However, it's not necessary at all. Operands used in arithmetic operators can be literals as well. For example, 
result = number1 + 5.2;
result = 2.3 + 4.5;
number2 = number1 -2.9;

Unary Operators

Unary operator performs operation on only one operand.
Operator Meaning
+ Unary plus (not necessary to use since numbers are positive without using it)
- Unary minus; inverts the sign of an expression
++ Increment operator; increments value by 1
-- decrement operator; decrements value by 1
! Logical complement operator; inverts the value of a boolean

Example 3: Unary Operator 

class UnaryOperator {
    public static void main(String[] args) {
     
     double number = 5.2, resultNumber;
     boolean flag = false;
     
     System.out.println("+number = " + +number);
     // number is equal to 5.2 here.
     
     System.out.println("-number = " + -number);
     // number is equal to 5.2 here.
     
        // ++number is equivalent to number = number + 1
     System.out.println("number = " + ++number);
        // number is equal to 6.2 here.
        // -- number is equivalent to number = number - 1
     System.out.println("number = " + --number);
        // number is equal to 5.2 here.
     System.out.println("!flag = " + !flag);
     // flag is still false.
    }
}
When you run the program, the output will be: 
+number = 5.2
-number = -5.2
number = 6.2
number = 5.2
!flag = true
Simple enough till now. However, there is a crucial difference while using increment and decrement operator as prefix and postfix. Consider this example,
Example 4: Unary Operator 
class UnaryOperator {
    public static void main(String[] args) {  
     double number = 5.2;
     System.out.println(number++);
     System.out.println(number);
     System.out.println(++number);
     System.out.println(number);
    }
}
When you run the program, the output will be: 
5.2
6.2
7.2
7.2
When System.out.println(number++); statement is executed, the original value is evaluated first. The number is increased only after that. That's why you are getting 5.2 as an output. Then, when System.out.println(number); is executed, the increased value 6.2 is displayed.
However, when System.out.println(++number); is executed, number is increased by 1 first before it's printed on the screen. Similar is the case for decrement -- operator.

Relational Operators

The equality and relational operators determines the relationship between two operands. It checks if an operand is greater than, less than, equal to, not equal to and so on. Depending on the relationship, it results to either true or false.
Operator Description Example
== equal to 5 == 3 is evaluated to false
!= not equal to 5 != 3 is evaluated to true
> greater then 5 > 3 is evaluated to true
< less then 5 < 3 is evaluated to false
>= greater then or equal to 5 >= 5 is evaluated to true
<= less then or equal to 5 <= 5 is evaluated to true

Equality and relational operators are used in decision making and loops (which will be discussed later). For now, check this simple example.
Example 5: Equality and Relational Operators

class RelationalOperator {
    public static void main(String[] args) {
     
     int number1 = 5, number2 = 6;
     if (number1 > number2)
     {
      System.out.println("number1 is greater than number2.");
     }
     else
     {
      System.out.println("number2 is greater than number1.");
     }
    }
}
When you run the program, the output will be: 
number2 is greater than number1.
Here, we have used > operator to check if number1 is greater than number2 or not.
Since, number2 is greater than number1, the expression number1 > number2 is evaluated to false.
Hence, the block of code inside else is executed and the block of code inside if is skipped.
If you didn't understand the above code, don't worry. You will learn it in detail in Java if...else article.
For now, just remember that the equality and relational operators compares two operands and is evaluated to either true or false.

Logical Operators

The logical operators || (conditional-OR) and && (conditional-AND) operates on boolean expressions. Here's how they work.
Operator Description Example
|| conditional-OR; true if either of the boolean expression is true false || true is evaluated to true
&& conditional-AND; true if all boolean expressions are true false && true is evaluated to false

Example 6: Logical Operators 

class LogicalOperator {
    public static void main(String[] args) {
     
     int number1 = 1, number2 = 2, number3 = 9;
     boolean result;
     
     // At least one expression needs to be true for result to be true
     result = (number1 > number2) || (number3 > number1);
     // result will be true because (number1 > number2) is true
     System.out.println(result);
       
     // All expression must be true from result to be true 
     result = (number1 > number2) && (number3 > number1);
     // result will be false because (number3 > number1) is false
     System.out.println(result);
    }
}
When you run the program, the output will be: 
true
false

Bitwise and Bit Shift Operators

To perform bitwise and bit shift operators in Java, these operators are used.
Operator Description
~ Bitwise Complement
<< Left Shift
>> Right Shift
>>> Unsigned Right Shift
& Bitwise AND ^
^ Bitwise exclusive OR
| Bitwise inclusive OR

Assignment Operators

We have only discussed about one assignment operator = in the beginning of the article. Except this operator, there are quite a few assignment operators that helps us to write cleaner code.
Operator Description Example
+= x += 5 x = x + 5
-= x *= 5 x = x * 5
/= x /= 5 x = x / 5
%= x %= 5 x = x / 5
<<= x <<= 5 x << 5
>>= x >>= 5 x = x >> 5
|= x |= 5 x = x | 5
^= x ^= 5 x = x ^ 5
&= x &= 5 x = x & 5

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