Given the code fragment: 1. ArrayList<Integer> list = new ArrayList<>(); 2. list.add(1001); 3. list.add(1002); 4. System.out.println(list.get(list.size())); What is the result?

Question

Options

• ACompilation fails due to an error on line 1.
• BAn exception is thrown at run time due to error on line 3
• CAn exception is thrown at run time due to error on line 4
• D1002

• A
  9% (5)
• B
  5% (3)
• C
  84% (46)
• D
  2% (1)

Explanation

Option C is correct because list.size() returns 2 (there are two elements), but ArrayList uses zero-based indexing, meaning valid indices are 0 and 1. Calling list.get(2) attempts to access a non-existent element, throwing an IndexOutOfBoundsException at runtime on line 4.

Why the distractors are wrong:

• A is wrong - line 1 is perfectly valid; the diamond operator <> has been supported since Java 7.
• B is wrong - line 3 adds 1002 to the list without any issue; ArrayList.add() does not throw an exception here.
• D is wrong - to get 1002 (the last element), you'd need list.get(list.size() - 1), i.e., index 1.

Memory tip: Think of it as a "fencepost" rule - a list of n elements has indices 0 through n-1. size() always equals the count, which is always one past the last valid index. When you see list.get(list.size()), spot the missing - 1 immediately.

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