Multiple choice

What will be the output of the program? public class WrapTest { public static void main(String [] args) { int result = 0; short s = 42; Long x = new Long("42"); Long y = new Long(42); Short z = new Short("42"); Short x2 = new Short(s); Integer y2 = new Integer("42"); Integer z2 = new Integer(42);

if (x == y) /* Line 13 / result = 1; if (x.equals(y) ) / Line 15 / result = result + 10; if (x.equals(z) ) / Line 17 / result = result + 100; if (x.equals(x2) ) / Line 19 / result = result + 1000; if (x.equals(z2) ) / Line 21 */ result = result + 10000;

System.out.println("result = " + result); } }

  1. result = 1

  2. result = 10

  3. result = 11

  4. result = 11010
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Line 13 fails because == compares reference values, not object values. Line 15 succeeds because both String and primitive wrapper constructors resolve to the same value (except for the Character wrapper). Lines 17, 19, and 21 fail because the equals()method fails if the object classes being compared are different and not in the same tree hierarchy.

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