Logical operators in Java - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of combined logical operators

What is the output of the following Java code snippet?

Java

public class Test {
    public static void main(String[] args) {
        boolean a = true;
        boolean b = false;
        boolean c = true;
        if (a && b || c) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
}

A Compilation error

B NO

C YES

D Runtime exception

💡 Hint

Remember the precedence of && and || operators in Java.

The expression a && b || c is evaluated as (a && b) || c. Since a && b is false, but c is true, the overall expression is true, so "YES" is printed.

❓ Predict Output

intermediate

Logical operator short-circuit behavior

What will be the output of this Java program?

Java

public class Test {
    public static void main(String[] args) {
        int x = 0;
        if (false && (++x > 0)) {
            System.out.println("Inside if");
        }
        System.out.println(x);
    }
}

A 1

B Runtime exception

C Compilation error

D 0

💡 Hint

Consider if the increment happens when the first condition is false in &&.

The && operator short-circuits. Since the first condition is false, ++x is not evaluated, so x remains 0.

❓ Predict Output

advanced

Output with mixed logical operators and precedence

What is the output of this Java code?

Java

public class Test {
    public static void main(String[] args) {
        boolean a = false;
        boolean b = true;
        boolean c = false;
        if (a || b && c) {
            System.out.println("TRUE");
        } else {
            System.out.println("FALSE");
        }
    }
}

A FALSE

B TRUE

C Compilation error

D Runtime exception

💡 Hint

Remember that && has higher precedence than ||.

The expression is evaluated as a || (b && c). Since b && c is false, and a is false, the whole expression is false, so "FALSE" is printed.

❓ Predict Output

advanced

Logical NOT operator effect

What will be printed by this Java program?

Java

public class Test {
    public static void main(String[] args) {
        boolean flag = true;
        if (!flag || flag && false) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
}

A NO

B YES

C Compilation error

D Runtime exception

💡 Hint

Evaluate the expression step by step, considering operator precedence and NOT operator.

The expression !flag || flag && false is (!flag) || (flag && false). Since flag is true, !flag is false and flag && false is false, so the whole expression is false || false = false. So the output should be "NO". The correct answer is B.

❓ Predict Output

expert

Complex logical expression evaluation

What is the output of this Java program?

Java

public class Test {
    public static void main(String[] args) {
        boolean a = true;
        boolean b = false;
        boolean c = true;
        boolean d = false;
        if ((a || b) && !(c && d) || b && !a) {
            System.out.println("PASS");
        } else {
            System.out.println("FAIL");
        }
    }
}

A Runtime exception

B PASS

C Compilation error

D FAIL

💡 Hint

Break down the expression into parts and evaluate carefully.

Evaluate stepwise:
1. (a || b) = true
2. (c && d) = false
3. !(c && d) = true
4. (a || b) && !(c && d) = true && true = true
5. b && !a = false && false = false
6. Overall: true || false = true
So "PASS" is printed.