ArrayList Practice Questions

Front

What method is used to get the number of elements in an ArrayList?

Back

size()

Front

Which of the following is NOT true about ArrayLists?
They can hold primitive types directly,
They are mutable,
They are part of the java.util package,
They can change size during runtime

Back

They can hold primitive types directly

Front

Why do ArrayLists use get and set methods instead of the index operator?

Back

Because ArrayLists are a class with methods.

Front

Which statement below is the correct way to retrieve the first element in the nums ArrayList? Options: nums.get(0), nums[0], nums(0), nums[1]

Back

nums.get(0)

Front

What is the starting index of an ArrayList?

Back

0

Front

What happens automatically when primitive types are added to an ArrayList?

Back

They are wrapped in objects.

Front

What is the correct way to add an integer to an ArrayList in all Java versions? Options: list.add(new Integer(5));, list.add(5);, list.add(Integer.valueOf(5));, list.add(5.0);

Back

list.add(5);

Front

What happens when you use the add(index, obj) method in an ArrayList?

Back

It adds the object at the index and shifts others.

Front

Which method would you use to replace an element at a specific index in an ArrayList? Options: set(int index, E obj), replace(int index, E obj), modify(int index, E obj), change(int index, E obj)

Back

set(int index, E obj)

Front

What will be printed?
List<Integer> list1 = new ArrayList<Integer>();
list1.add(5);
list1.add(4);
list1.add(3);
list1.add(1, 2);
System.out.println(list1);

Back

[5, 2, 4, 3]