Identify the correct outcome of this Java switch with comma-separated labels (which are invalid in Java). What happens at compile time?\n\nint i = l, j = -1; // Note: the source uses the letter l, not digit 1\nswitch (i)\n{\n case 0, 1: j = 1; // invalid Java syntax (comma in case label)\n case 2: j = 2;\n default: j = 0;\n}\nSystem.out.println("j = " + j);

Difficulty: Easy

Correct Answer: Compilation fails.

Explanation:


Introduction / Context:
This question checks knowledge of valid switch syntax and identifier usage in Java. It intentionally includes two separate compile-time problems to see if you can spot either.


Given Data / Assumptions:

  • The initializer uses int i = l; where l is a lowercase letter, not the digit 1, and is undefined.
  • The case line uses case 0, 1:, which is not legal Java syntax (Java does not allow comma-separated case labels on one line).


Concept / Approach:
Java requires each case label to be written individually, for example case 0: on one line, case 1: on another. Also, every variable must be declared before use. Either violation causes compilation to fail.


Step-by-Step Solution:
Undefined identifier: l has no declaration ⇒ compile-time error.Invalid syntax: case 0, 1: also triggers a syntax error.Because compilation fails, the program produces no runtime output.


Verification / Alternative check:
Fix the code to int i = 1; and use separate labels case 0: and case 1:; then re-run to observe normal behavior.


Why Other Options Are Wrong:
All printed results assume successful compilation and execution, which cannot happen given the errors.


Common Pitfalls:
Confusing the letter l with the digit 1; thinking comma-separated case labels are valid in Java (they are not).


Final Answer:
Compilation fails.

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