Question 1

Given the following generic method, which of the following is a possible return type? public static > E max(E[] a) { ...} i.String II.Object III.Double

Accepted Answer

A) I only 
B) I and III only 
C) II only 
D) I and II only

Question 2

Consider the following code snippet: public class LinkedList { private E defaultValue; public static List replicate(E value, int n) { ...} private class Node { public String data; public Node next;) ... } What is wrong with this code?

Accepted Answer

A) Cannot pass a generic type as an argument to a method. 
B) Cannot have a static method in a generic class as shown. 
C) Cannot have an inner class in a generic class. 
D) Cannot declare the variable defaultValue as a generic type.

Question 3

Consider the following code snippet:
public class LinkedList<E>
{
private E defaultValue;
public void add(E value, int n) { ...}
private static class Node { public E data; public Node next; }
...
}
What is wrong with this code?

Accepted Answer

A) Cannot declare the variable defaultValue as a generic type. 
B) Cannot pass a generic type as an argument to a method. 
C) Cannot have a static method in a generic class as shown. 
D) Cannot have a static inner class in a generic class as shown.

Question 4

Consider the following code snippet: public class Box { private E data; public Box(){ ...} public void insert(E value) { ...} public E getData() { ...} } What will result from executing the following code? Box box = new Box<>(); ... box.insert("blue Box"); String b = (String) box.getData();

Accepted Answer

A) correct, with necessary cast 
B) run-time error 
C) compiler error 
D) correct, but unnecessary cast

Question 5

In Java, generic programming can be achieved with ____.

Accepted Answer

A) polymorphism 
B) arrays 
C) encapsulation 
D) inheritance

Question 6

Which of the following is not a wildcard type?

Accepted Answer

A) (?) sub B 
B) (?) extends B 
C) (?) super B 
D) (?)

Question 7

Which Java technique(s) allows generic programming?
i.type variables
II.primitive types
III.inheritance

Accepted Answer

A) I only 
B) I and III only 
C) III only 
D) II only

Question 8

Consider the following code snippet: public static > E min(ArrayList objects) What can we conclude about the return type of this method?

Accepted Answer

A) The return type is a subclass of the ArrayList class. 
B) The return type is a class that implements Comparable. 
C) The return type is a class that extends Comparable. 
D) The return type is an array list of generic objects.

Question 9

Consider the following code snippet: public class Box { private E data; public Box(){ ...} public void insert(E value) { ...} public E getData(){ ...} } What specific exception will be thrown when the following code executes? Box box = new Box<>(); ... box.insert("blue Box"); Double myDouble = (Double) box.getData();

Accepted Answer

A) ClassCastException 
B) Exception 
C) IndexOutOfBoundsException 
D) NoSuchElementException

Question 10

Select the correct header for this generic print method.
public static void print(E[] a)
{
for (int i = 0; i < a.length; i++)
{
System.out.println(a[i] + " ");
}
}

Accepted Answer

A) The header is correct B) public void print(E [] a) C) public static void print(E a) D) public static void print(E[] a)

Question 11

Consider the following class declaration:
public class SavingsAccount extends BankAccount
{ ...}
Which of the following statements about these classes is correct?

Accepted Answer

A) ArrayList is a subclass of ArrayList. B) ArrayList is a subclass of ArrayList. C) There is no relationship between ArrayList and ArrayList D) ArrayList extends ArrayList.

Question 12

Consider the following code snippet:
public static <E> void print(E [] a)
{
for (int i = 0; i < a.length; i++)
{
System.out.println(a[i] + " ");
}
}
int[] a = {3,6,5,7,8,9,2,3};
String[] s = {"happy","cat","silly","dog"};
Boolean[] b = {true, true, false};
Which of the following are correct calls to this generic print method?
i.print(a);
II.print(s);
III.print(b);

Accepted Answer

A) II and III only 
B) I and II only 
C) I, II and III 
D) I only

Question 13

Which argument type cannot be passed to generic methods?
i.Object
II.GUI components
III.primitive

Accepted Answer

A) III only 
B) I only 
C) II only 
D) I and III only

Question 14

Which of the following statements about the Java virtual machine is correct?

Accepted Answer

A) The Java virtual machine always replaces type parameters with their lower bounds. 
B) The Java virtual machine always replaces type parameters with their upper bounds. 
C) The Java virtual machine replaces type parameters with their bounds or with type Object. 
D) The Java virtual machine always replaces type parameters with type Object.

Question 15

Consider the following code snippet: ArrayList arr = new ArrayList<>(); String element = arr.get(0); Is there an error in this code?

Accepted Answer

A) No run-time error or compile-time errors will occur. 
B) Yes, a compile-time error will occur because you cannot create an ArrayList of type Double. 
C) Yes, a run-time error will occur because a Double value cannot be cast to a String value. 
D) Yes, a compile-time error will occur because you cannot assign a Double value to a String variable.

Question 16

Which code is the equivalent of the following method header? public static void abc(Stack stack) { ...} i.public static void abc(Stack stack) { ...} II.public static

Accepted Answer

A) II only 
B) I only 
C) III only 
D) I and III only

Question 17

Consider the following code snippet: public class Box { private E data; public Box() { ...} public void insert(E value) { ...} public E getData() { ...} } What will result from executing the following code? Box box = new Box<>(); Box b = (Box) box.getData();

Accepted Answer

A) correct generic assignment 
B) run-time error 
C) compile-time warning 
D) compile-time error

Question 18

Which of the following are restrictions of Java generic programming?
i.You cannot use the assignment operator = to assign one generic object to another.
II.You cannot use the == operator to compare two generic objects.
III.You cannot construct arrays of generic types.

Accepted Answer

A) II only 
B) III only 
C) I only 
D) I and III only

Question 19

Given the following declaration, what is the type parameter in Stack<E> replaced with?
private Stack myStack = new Stack();

Accepted Answer

A) String 
B) Object 
C) it is a compiler error 
D) int

Question 20

Generics limit Java code somewhat.Which of the following are considered limitations of generic code?
i.cannot have an array of a generic type
II.cannot have primitive type variables
III.cannot construct an object of a generic type

Accepted Answer

A) I only 
B) I, II and III 
C) II only 
D) III only

Exam 18: Generic Classes

Given the following generic method, which of the following is a possible return type? public static <E extends Comparable<E>> E max(E[] a) { ...} i.String II.Object III.Double

Consider the following code snippet: public class LinkedList<E> { private E defaultValue; public static List<E> replicate(E value, int n) { ...} private class Node { public String data; public Node next;) ... } What is wrong with this code?

Consider the following code snippet: public class LinkedList<E> { private E defaultValue; public void add(E value, int n) { ...} private static class Node { public E data; public Node next; } ... } What is wrong with this code?

In Java, generic programming can be achieved with ____.

Which of the following is not a wildcard type?

Which Java technique(s) allows generic programming? i.type variables II.primitive types III.inheritance

Consider the following code snippet: public static <E extends Comparable<E>> E min(ArrayList<E> objects) What can we conclude about the return type of this method?

Select the correct header for this generic print method. public static void print(E[] a) { for (int i = 0; i < a.length; i++) { System.out.println(a[i] + " ") ; } }

Consider the following class declaration: public class SavingsAccount extends BankAccount { ...} Which of the following statements about these classes is correct?

Which argument type cannot be passed to generic methods? i.Object II.GUI components III.primitive

Which of the following statements about the Java virtual machine is correct?

Consider the following code snippet: ArrayList<Double> arr = new ArrayList<>() ; String element = arr.get(0) ; Is there an error in this code?

Which code is the equivalent of the following method header? public static <E> void abc(Stack<E> stack) { ...} i.public static void abc(Stack<?> stack) { ...} II.public static <Object> void abc (Stack<Object> stack) { ...} III.public static void abc(Stack stack) { ...}

Consider the following code snippet: public class Box<E> { private E data; public Box() { ...} public void insert(E value) { ...} public E getData() { ...} } What will result from executing the following code? Box<Boolean> box = new Box<>() ; Box b = (Box) box.getData() ;

Which of the following are restrictions of Java generic programming? i.You cannot use the assignment operator = to assign one generic object to another. II.You cannot use the == operator to compare two generic objects. III.You cannot construct arrays of generic types.

Given the following declaration, what is the type parameter in Stack<E> replaced with? private Stack myStack = new Stack() ;

Generics limit Java code somewhat.Which of the following are considered limitations of generic code? i.cannot have an array of a generic type II.cannot have primitive type variables III.cannot construct an object of a generic type