Java Bitwise and Logical Operators Result

1Z0-829 By islever Editorial Last updated

Handling date, time, text, numeric and boolean values

Short answer

A The program outputs 'false 0' followed by 'true 1' due to bitwise complement calculation and short-circuit logical evaluation.

Question

Given the code fragment: What is the result? - Exhibit: Java Bitwise and Logical Operators Result
  1. false 0 Correct Answer
  2. false 1
  3. true 1
  4. false 1

Key Takeaways

The key insight is understanding that ~2 results in -3, making a < b false, while a > c++ evaluates to true only when using the logical && operator after c remains 0.

This question tests the evaluation of bitwise NOT, XOR, AND, and logical AND operators with short-circuit behavior in Java. The correct output is false 0 followed by true 1.

Common mistake: Candidates often miscalculate the bitwise NOT (~a) or confuse the short-circuit behavior of && with the non-short-circuit &, leading to incorrect boolean values or incremented counter states.

Expert Analysis

Why the Answer Is Correct

The code initializes int a = 2. The expression int b = ~a computes the bitwise complement of 2 (binary...0010), resulting in -3 (binary...1101). Then int c = a ^ b computes 2 XOR -3. Since 2 is...0010 and -3 is...1101, the XOR result is...1111 which is -1? Wait, let's re-evaluate. Actually, looking at the comments, user james2033 provides the trace: false 0 then true 1. Let's verify. a=2, b=-3. c = 2 ^ (-3). 2 is 0...010. -3 is 1...101. XOR is 1...111 which is -1. So c becomes -1 initially? No, wait. The comment says c starts as something else? Ah, the variable c is declared as int c = a ^ b. If a=2 and b=-3, c is -1. However, the options show 0 and 1. Let's look closer at the image or standard trick. Usually, these questions involve post-increment side effects. Let's re-read the likely code structure from the comment: boolean d = a < b & a > c++;. Here c is used in c++. If c was initialized to 0? No, c = a ^ b. If a=2 and b is something else? Maybe b is not ~a? The text says int b = ~a. Let's trust the community consensus and the detailed trace provided by james2033 which matches Option A. The trace shows d is false because 2 < -3 is false. The & operator evaluates both sides, but since the left side is false, the right side 2 > c++ is still evaluated? No, & is not short-circuiting. But if d is false, does it print false 0? This implies c was 0 before increment? Or c became 0? Actually, if a=2 and b=~a=-3, then c = 2 ^ -3 = -1. Then a > c++ is 2 > -1 which is true. So d = false & true is false. And c increments from -1 to 0. So first line prints false 0. Next line: boolean e = a > b && a > c++;. a > b is 2 > -3 which is true. Short-circuit? No, next part a > c++. c is now 0. 2 > 0 is true. c increments to 1. So e is true. Second line prints true 1. Thus, the output is: false 0 true 1 This matches Option A.

Exam Strategy

Always calculate bitwise complements carefully (remember they flip all bits including sign). Pay close attention to whether you are using single & or double &&/|/|| to determine if short-circuiting occurs, especially when side effects like ++ are involved.

Frequently Asked Questions

Why is the first output 'false 0' instead of 'false -1'?

The variable c is incremented via c++. It starts at -1 (from XOR), so the comparison uses -1, then c becomes 0. The printed value is the post-incremented c.

What is the difference between & and && in this context?

& always evaluates both operands. && short-circuits if the left operand is false. Here, the second line uses &&, but both sides were true anyway.

More 1Z0-829 FAQ →

Community Votes

A
100%

100% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 6 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 6

  1. Tojose 👍 7
    the right answer is A. false 0 true 1
  2. james2033 👍 4 Answered A
    package q26; public class Q26 { public static void main(String[] args) { int a = 2; int b = ~a; int c = a ^ b; boolean d = a < b & a > c++; System.out.println(d + " " + c); boolean e = a > b && a > c++; System.out.println(e + " " + c); } } // Result: // false 0 // true 1
  3. SrinivasJasti 👍 1 Answered A
    ~ inverts the value in binary, ^ compares binary
  4. 9817c20 👍 1
    how the fook can one calculate a^b in ones head?
  5. zuluitai 👍 1
    The correct answer is A.
Show 1 more comment
  1. xplorerpj 👍 1
    Correct answer is A

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