Syntax

{condition-to-evaluate} ? {statement-executed-on-true} : {statement-executed-on-false}

As shown in the syntax, the Conditional Operator (also known as the Ternary Operator1) uses the ? (question mark) and : (colon) characters to enable a conditional expression of two possible outcomes. It can be used to replace longer if-else blocks to return one of two values based on condition.

result = testCondition ? value1 : value2

Is equivalent to

if (testCondition) { 
    result = value1; 
} else { 
    result = value2; 
}

It can be read as “If testCondition is true, set result to value1; otherwise, set result to value2”.

For example:

// get absolute value using conditional operator 
a = -10;
int absValue = a < 0 ? -a : a;
System.out.println("abs = " + absValue); // prints "abs = 10"

Is equivalent to

// get absolute value using if/else loop
a = -10;
int absValue;
if (a < 0) {
    absValue = -a;
} else {
    absValue = a;
}
System.out.println("abs = " + absValue); // prints "abs = 10"

Common Usage

You can use the conditional operator for conditional assignments (like null checking).

String x = y != null ? y.toString() : ""; //where y is an object

This example is equivalent to:

String x = "";

if (y != null) {
    x = y.toString();
}

Since the Conditional Operator has the second-lowest precedence, above the Assignment Operators, there is rarely a need for use parenthesis around the condition, but parenthesis is required around the entire Conditional Operator construct when combined with other operators:

// no parenthesis needed for expressions in the 3 parts
10 <= a && a < 19 ? b * 5 : b * 7

// parenthesis required
7 * (a > 0 ? 2 : 5)

Conditional operators nesting can also be done in the third part, where it works more like chaining or like a switch statement.