Logical Operators in Java

Logical Operators in Java

Introduction

Logical operators in Java are used to perform logical operations on boolean values. They help in decision-making expressions and are often combined with relational operators. The result of a logical operation is always true or false.

Logical Operators in Java

Java provides three primary logical operators:

Logical AND (&&) Operator :

• The AND (&&) operator returns true only if both conditions are true.

• If the first condition is false, the second condition is not evaluated.

Truth Table for AND (&&):

Java - Truth Table - AND

Example 1: AND Operator:

class Main {

    public static void main(String[] args) {

        System.out.println((2 < 3) && (1 < 2));  // true

    }

}

Explanation:

• (2 < 3) && (1 < 2)

• true && true → true

Example 2: AND Operator with a False Condition :

class Main {

    public static void main(String[] args) {

        System.out.println((10 < 5) && (6 < 9));   // false

    }

}

Explanation:

• (10 < 5) && (6 < 9)

• false && (6 < 9)

• Since the first condition is false, Java does not check the second condition.

Logical OR (||) Operator :

• The OR (||) operator returns true if at least one condition is true.

• If the first condition is true, the second condition is not checked.

Java - OR operator

Example 1: OR Operator:

class Main {

    public static void main(String[] args) {

        System.out.println((12 > 13) || (15 < 12));  // false

    }

}

Explanation:

• (12 > 13) || (15 < 12)

• false || false → false

Example 2: OR Operator with a True Condition :

class Main {

    public static void main(String[] args) {

        System.out.println((2 < 3) || (2 < 1));  // true

    }

}

Explanation:

(2 < 3) || (2 < 1)
true || (2 < 1)
Since the first condition is true, Java does not check the second condition.

Logical NOT (!) Operator:

• The NOT (!) operator is a unary operator that inverts the boolean value.

• If a condition is true, applying ! makes it false, and vice versa.

java - Logical NOT Operator

Example 1: NOT Operator:

class Main {

    public static void main(String[] args) {

        System.out.println(!(5 > 7));  // true

    }

}

Explanation:

• !(5 > 7) → !(false) → true

Example 2: NOT Operator with a True Condition :

class Main {

    public static void main(String[] args) {

        System.out.println(!(2 < 3));  // false

    }

}

Explanation:

• !(2 < 3) → !(true) → false

Summary

• Logical AND (&&) returns true only if both conditions are true.

• Logical OR (||) returns true if at least one condition is true.

• Logical NOT (!) reverses the boolean value.