In Java (operators, short-circuiting, and identifiers), what is the output of this program or what error occurs? public class ExamQuestion6 { static int x; boolean catch() { x++; return true; } public static void main(String[] args) { x = 0; if ((catch() | catch()) || catch()) x++; System.out.println(x); } }

Difficulty: Easy

Correct Answer: Compilation Fails

Explanation:


Introduction / Context:
This question examines two ideas: (1) whether Java allows keywords as identifiers, and (2) the evaluation behavior of | versus ||. The crucial blocker here is the method name catch, which is a reserved keyword in Java and cannot be used as an identifier.


Given Data / Assumptions:

  • Method declared as boolean catch() in the same class.
  • The main method is static; even if naming were legal, calling an instance method without an instance would also be problematic unless qualified.


Concept / Approach:
Java’s reserved words (e.g., catch, try, class) cannot be used as method or variable names. Therefore, the code fails to compile before any runtime evaluation occurs. If it were renamed (e.g., call()) and made static or invoked on an instance, note that | (bitwise-or on booleans) evaluates both operands (no short-circuit), while || short-circuits the right operand when the left is true.


Step-by-Step Solution:

Compilation stage: identifier catch conflicts with Java keyword → error. Program does not execute; no output is produced.


Verification / Alternative check:
Renaming the method to f() and making it static, the expression (f() | f()) || f() would call f() twice on the left (because | is non–short-circuit) and possibly skip the final f() depending on results.


Why Other Options Are Wrong:

  • Numeric outputs assume successful compilation and execution, which do not occur.
  • Runtime Exception: never reached due to compile failure.


Common Pitfalls:
Forgetting that some symbols cannot be identifiers; also mixing up | (always evaluates both sides) vs || (short-circuits).


Final Answer:
Compilation Fails

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion