Chapter 13

Which of the following is a true statement?

• Once created, an array cannot be resized.
• When an array of objects is created using the new operator, its elements get random values.
• Arrays never hold duplicate values.
• Arrays can not be sorted.

What happens when the number of elements in an ArrayList<SomeType> list has reached its capacity and you call list.add(x)?

• A larger array is allocated, the values from the old array are copied into the new array, then x is appended to the list.
• The list remains unchanged and add returns false.
• IllegalStateException
• ArrayIndexOutOfBoundsException

Which of the following is a true statement?

• java.util.ArrayList<E> extends java.util.List<E>.
• An ArrayList<Object> can hold objects of any type.
• An ArrayList<boolean> holds Boolean values.
• An ArrayList<int> holds Integer values.

Which of the following is a true statement?

• An ArrayList<String> holds references to String objects.
• An ArrayList<String> can also hold references to Object objects.
• An ArrayList<Double> can also hold references to Integer objects, due to the principle of narrowing.
• An ArrayList<Integer> can also hold references to Double objects due to the principle of widening.

Which of the following is a true statement?

• The same object can simultaneously belong to an array and to an ArrayList.
• After it has been added to an ArrayList, an object cannot change.
• If an ArrayList<Object> lst already contains an object x, you cannot add x again at the end of lst — a lst.add(x) call will return false. 
• ArrayLists automatically filter out duplicates.

The ArrayList class has a constructor that takes one int parameter. new ArrayList<Object>(n)creates an ArrayList with the

• capacity n and size 0.
• capacity n and size n, with all the elements set to null.
• capacity 2*n and size n, with all the elements set to null.
• default capacity or capacity n, whichever is larger, and size 0. 

Which of the following ArrayList<E>’s methods returns an object of the type E?

• get and set
• rename and replace
• contains and isEmpty
• toString and size

Suppose list is an ArrayList<Integer> and n == list.size().  Which of the following calls will throw an IndexOutOfBoundsException?

• list.get(n);
• list.add(n, 0);
• list.remove(0);
• list.replace(0);

What does ArrayLists’s toString method return?

• String representations of its elements (returned by the calls to their respective toString methods) within square brackets, with consecutive elements separated by a comma and a space
• String representations of its elements (returned by the calls to their respective toString methods) concatenated into one string
• The size and capacity of the ArrayList within parentheses, separated by a comma and a space
• ArrayList does not override Object’s toString method 

What are the contents of farm after the following code segment is executed?

• "pigs", "cows", "sheep"
• "pigs", "sheep", "cows"
• "cows", "sheep", "pigs"
• "sheep", "cows", "pigs"