Java Operators

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

1. Java Operators

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

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 is called a unary operator; if it takes two operands, it is called a binary operator; if it takes three operands, it is 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.

Let us learn about few most used operators with examples.

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

3.2. Binary Arithmetic Operators

4. String Concatenation Operator

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

4.1. Concatenating 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

4.2. Concatenating Primitive Types 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

4.3. 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.

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.

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.

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.

boolean-expression ? true-expression : false-expression

int number1 = 40;
int number2 = 20;

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

//Compares both numbers and return which one is bigger

9. Operators 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 the precedence of multiplication is higher than addition.

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

That’s all for the operators in java.

Happy Learning !!