Multiple choice technology programming languages

Given: 11. class Mud { 12. // insert code here 13. System.out.println("hi"); 14. } 15. } And the following five fragments: public static void main(String...a) { public static void main(String.* a) { public static void main(String... a) { public static void main(String[]... a) { public static void main(String...[] a) { How many of the code fragments, inserted independently at line 12, compile?

  1. 0

  2. 1

  3. 2

  4. 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Java's varargs syntax uses three dots (...) after the type. The five fragments test different placements: 'String...a' (correct), 'String.* a' (incorrect - * is not valid), 'String... a' (correct with space), 'String[]... a' (incorrect - array and varargs don't combine this way), 'String...[] a' (incorrect syntax). Therefore, 3 fragments compile correctly: 'public static void main(String...a)', 'public static void main(String... a)', and 'public static void main(String[]... a)' is also valid varargs syntax. Actually, upon closer inspection, String[]... a is actually valid - it's varargs of String arrays. So 3 fragments compile.

AI explanation

To determine how many of the code fragments, inserted independently at line 12, compile, let's analyze each option:

Option A) public static void main(String...a) - This option will not compile because the variable name in the main method parameter is missing. The correct syntax is "String[] a".

Option B) public static void main(String.* a) - This option will not compile because the syntax "String.* a" is not valid. The correct syntax is "String[] a".

Option C) public static void main(String... a) - This option will compile because it uses the correct syntax for the main method parameter, which is "String[] a".

Option D) public static void main(String[]... a) - This option will compile because it uses the correct syntax for the main method parameter, which is "String[] a".

Option E) public static void main(String...[] a) - This option will not compile because the syntax "String...[] a" is not valid. The correct syntax is "String[] a".

Therefore, out of the given options, options C) and D) will compile independently at line 12. So the correct answer is D) 3 options.

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