Java Operators Example

Java Operators Output Questions: 35 Practice Problems with Answers (2026)

Java Operators Output Questions: 35 Practice Problems with Answers

These 35 Java operator output questions are designed to test your understanding of how Java evaluates expressions — especially the tricky behavior of prefix vs postfix operators, arithmetic precedence, and type rules.

Each question presents a small program. Try to predict the output before checking the answer. This is one of the best ways to prepare for Java interviews and certifications.

Questions 1–10: Prefix, Postfix & Compound Expressions

Q1. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i + i++ - i);
    }
}

Output: 10

Explanation: i++ returns 10 and then i becomes 11. So the expression is 10 + 10 - 11 = 9... wait, let me re-evaluate:

  • i is 10 → first operand is 10
  • i++ returns 10 and increments i to 11 → second operand is 10
  • Now i is 11 → third operand is 11
  • Result: 10 + 10 - 11 = 9

Corrected output: 9

Q2. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i - i++ - i);
    }
}

Output: -11

Explanation: i - i++ - i → 10 - 10 - 11 = -11

Q3. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i--i + i);
    }
}

Output: Compile-time error

Explanation: i--i is tokenized as i-- followed by i. Two operands with no operator between them is invalid syntax.

Q4. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i---i++i);
    }
}

Output: Compile-time error

Explanation: Multiple invalid tokens — i---i is i-- then -i, but -i++i is not valid.

Q5. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i---i+++i);
    }
}

Output: Compile-time error

Explanation: Same tokenization problem — invalid expression.

Q6. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i--);
    }
}

Output: 10

Explanation: Postfix decrement returns the original value (10), then decrements i to 9.

Q7. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(--i);
    }
}

Output: 9

Explanation: Prefix decrement reduces i to 9 first, then returns 9.

Q8. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(++i);
    }
}

Output: 11

Explanation: Prefix increment first increments to 11, then returns 11.

Q9. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        i++;
        System.out.println(i);
    }
}

Output: 11

Explanation: Postfix increment on its own line increments i to 11.

Q10. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = -10;
        System.out.println(--i);
    }
}

Output: -11

Explanation: Prefix decrement reduces -10 to -11.

Questions 11–20: Arithmetic & Operator Precedence

Q11. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i + i);
    }
}

Output: 20

Q12. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i - i);
    }
}

Output: 0

Q13. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i * i);
    }
}

Output: 100

Q14. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i / i);
    }
}

Output: 1

Q15. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i + i / i);
    }
}

Output: 11

Explanation: Division has higher precedence than addition, so i + (i / i) = 10 + 1 = 11.

Q16. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i + i * i);
    }
}

Output: 110

Explanation: Multiplication first: 10 + (10 * 10) = 10 + 100 = 110.

Q17. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i + i * i / i);
    }
}

Output: 20

Explanation: 10 + (10 * 10 / 10) = 10 + 10 = 20.

Q18. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i + i * i / i + i);
    }
}

Output: 30

Explanation: 10 + 10 + 10 = 30.

Q19. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i + i / i * i % i);
    }
}

Output: 10

Explanation: 10 / 10 = 1, 1 * 10 = 10, 10 % 10 = 0, so 10 + 0 = 10.

Q20. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(i % 0);
    }
}

Output: Runtime exception: ArithmeticException

Explanation: Modulus by zero throws ArithmeticException at runtime.

Questions 21–30: Assignment & String Comparisons

Q21. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        System.out.println(0 % 2);
    }
}

Output: 0

Q22. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        i += 2;
        System.out.println(i);
    }
}

Output: 12

Explanation: i += 2 is the same as i = i + 2.

Q23. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        i = +2;
        System.out.println(i);
    }
}

Output: 2

Explanation: This is unary plus, not +=. So i is set to 2.

Q24. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        i = ++2;
        System.out.println(i);
    }
}

Output: Compile-time error

Explanation: ++ can only be applied to variables, not literals.

Q25. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 10;
        i = ++i;
        System.out.println(i);
    }
}

Output: 11

Explanation: ++i increments i to 11, then assigns it back to i.

Q26. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        char a = 'a';
        char b = 'c';
        System.out.println(b > a);
    }
}

Output: true

Explanation: Characters are compared by their Unicode values: 'c' (99) > 'a' (97) is true.

Q27. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        String a = "1";
        String b = "2";
        System.out.println(b > a);
    }
}

Output: Compile-time error

Explanation: Java does not allow > or < on String objects.

Q28. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        String a = "1";
        String b = "2";
        System.out.println(b = a);
    }
}

Output: 1

Explanation: b = a assigns a to b and returns the assigned value, which is "1".

Q29. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        String a = "1";
        String b = "2";
        System.out.println(b == a);
    }
}

Output: false

Explanation: == compares references for objects. Even identical content may not be the same reference.

Q30. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        String a = "1";
        String b = "2";
        System.out.println(b = !a);
    }
}

Output: Compile-time error

Explanation: ! can only be applied to boolean values, not Strings.

Questions 31–35: Relational & Ternary

Q31. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        String a = "1";
        String b = "2";
        System.out.println(b != a);
    }
}

Output: true

Explanation: != compares references. Since a and b are different objects, the result is true.

Q32. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        String a = "1";
        String b = "2";
        System.out.println(b <= a);
    }
}

Output: Compile-time error

Explanation: <= is not allowed on String objects.

Q33. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 12;
        int j = 21;
        System.out.println(i <= j);
    }
}

Output: true

Explanation: 12 is less than or equal to 21.

Q34. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 12;
        int j = 21;
        System.out.println(i > j ? "Right" : "Wrong");
    }
}

Output: Wrong

Explanation: 12 > 21 is false, so the ternary returns "Wrong".

Q35. What is the output of the following program?

public class B {
    public static void main(String[] args) {
        int i = 12;
        int j = 1;
        System.out.println(i > j);
    }
}

Output: true

Explanation: 12 is greater than 1.

Frequently Asked Questions

Why does i++ + ++i give different results in Java?

Postfix (i++) uses the current value and then increments. Prefix (++i) increments first and then uses the new value. When mixed in an expression, evaluation happens left to right, so i++ uses the old value while ++i uses the incremented value.

What is the output of i--i+i in Java?

This expression has a compile-time error because Java tokenizes i--i as i-- followed by i, which is two operands with no operator between them. It is not valid syntax.

What happens when you divide by zero in Java?

Dividing an integer by zero throws ArithmeticException at runtime. For floating-point numbers, dividing by zero returns Infinity or NaN instead of throwing an exception.

Can you compare two String objects using > in Java?

No. Java does not allow > or < on String objects. It causes a compile-time error. To compare strings, use equals() for content or compareTo() for lexicographic ordering.

What is the output of i % 0 in Java?

The modulus of an integer by zero throws ArithmeticException at runtime because the modulus operator performs an implicit division. The same exception occurs with i / 0 for integers.

Conclusion

These 35 Java operator output questions cover the most common pitfalls developers face — especially the tricky behavior of prefix vs postfix operators and precedence rules. Practice them until you can predict each output with confidence.

The most important lessons: i++ uses the old value, ++i uses the new value, division/modulus by zero throws an exception, and Strings cannot be compared with relational operators. Master these and you'll handle any Java operator interview question.

Related topics: Java Operators Complete Guide, Java Data Types Questions, Java Overloading Questions, Java Overriding Questions, Java Array Questions, Java Interview Questions

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