The equality and relational operators determine if one operand is greater than, less than, equal to, or not equal to another operand.

The majority of these operators will probably look familiar to you as well.

You must use "==", not "=", when testing if two primitive values are equal.

 
==      equal to
!=      not equal to
>       greater than
>=      greater than or equal to
<       less than
<=      less than or equal to

The following program, ComparisonDemo, tests the comparison operators:

 

class ComparisonDemo {

    public static void main(String[] args){
        int value1 = 1;
        int value2 = 2;
        if(value1 == value2)
            System.out.println("value1 == value2");
        if(value1 != value2)
            System.out.println("value1 != value2");
        if(value1 > value2)
            System.out.println("value1 > value2");
        if(value1 < value2)
            System.out.println("value1 < value2");
        if(value1 <= value2)
            System.out.println("value1 <= value2");
    }
}

Output:

 
value1 != value2
value1 <  value2
value1 <= value2

The && and || operators perform Conditional-AND and Conditional-OR operations on two boolean expressions.

These operators exhibit "short-circuiting" behavior, which means that the second operand is evaluated only if needed.

 
&& Conditional-AND
|| Conditional-OR

The following program, ConditionalDemo1, tests these operators:

 
class ConditionalDemo1 {

    public static void main(String[] args){
        int value1 = 1;
        int value2 = 2;
        if((value1 == 1) && (value2 == 2))
            System.out.println("value1 is 1 AND value2 is 2");
        if((value1 == 1) || (value2 == 1))
            System.out.println("value1 is 1 OR value2 is 1");
    }
}

Another conditional operator is ?:, which is a shorthand for an if-then-else statement.

This operator is also known as the ternary operator because it uses three operands.

In the following example, this operator should be read as: "If someCondition is true, assign the value of value1 to result. Otherwise, assign the value of value2 to result."

The following program, ConditionalDemo2, tests the ?: operator:

 

class ConditionalDemo2 {

    public static void main(String[] args){
        int value1 = 1;
        int value2 = 2;
        int result;
        boolean someCondition = true;
        result = someCondition ? value1 : value2;

        System.out.println(result);
    }
}

Because someCondition is true, this program prints "1" to the screen. Use the ?: operator instead of an if-then-else statement if it makes your code more readable;

for example, when the expressions are compact and without side-effects (such as assignments).

Equality, Relational, and Conditional Operators

The Conditional Operators