booleans.md

The type Boolean represents boolean objects that can have two values: true and false. Boolean has a nullable counterpart declared as Boolean?.

On the JVM, booleans stored as the primitive boolean type typically use 8 bits.

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Built-in operations on booleans include:

• || – disjunction (logical OR)
• && – conjunction (logical AND)
• ! – negation (logical NOT)

For example:

fun main() {
//sampleStart
    val myTrue: Boolean = true
    val myFalse: Boolean = false
    val boolNull: Boolean? = null

    println(myTrue || myFalse)
    // true
    println(myTrue && myFalse)
    // false
    println(!myTrue)
    // false
    println(boolNull)
    // null
//sampleEnd
}

{kotlin-runnable="true" kotlin-min-compiler-version="1.3"}

The || and && operators work lazily, which means:

• If the first operand is true, the || operator does not evaluate the second operand.
• If the first operand is false, the && operator does not evaluate the second operand.

On the JVM, nullable references to boolean objects are boxed in Java classes, just like with numbers.

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