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Question 1
Which implementation of the
List
interface produces the
slowest access to an element in the middle
of the list by means of an index?
| a. | Vector |
| b. | ArrayList |
| c. | LinkedList |
| d. | None of the above |
Question 2
import java.util.*;
class GFC100 {
public static void main (String args[]) {
Object a1 = new LinkedList(), b1 = new TreeSet();
Object c1 = new TreeMap();
System.out.print((a1 instanceof Collection)+",");
System.out.print((b1 instanceof Collection)+",");
System.out.print(c1 instanceof Collection);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false,false |
| b. | Prints: false,false,true |
| c. | Prints: false,true,false |
| d. | Prints: false,true,true |
| e. | Prints: true,false,false |
| f. | Prints: true,false,true |
| g. | Prints: true,true,false |
| h. | Prints: true,true,true |
| i. | None of the above |
Question 3
| | • | Each element must be unique. |
| | • | Contains no duplicate elements. |
| | • | Elements are not key/value pairs. |
| | • | Accessing an element can be almost as fast as performing a similar operation on an array. |
Which of these classes provides the specified features?
| a. | LinkedList |
| b. | TreeMap |
| c. | TreeSet |
| d. | HashMap |
| e. | HashSet |
| f. | LinkedHashMap |
| g. | Hashtable |
| h. | None of the above |
Question 4
import java.util.*;
class GFC101 {
public static void main (String args[]) {
Object a1 = new HashMap(), b1 = new ArrayList();
Object c1 = new HashSet();
System.out.print((a1 instanceof Collection)+",");
System.out.print((b1 instanceof Collection)+",");
System.out.print(c1 instanceof Collection);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false,false |
| b. | Prints: false,false,true |
| c. | Prints: false,true,false |
| d. | Prints: false,true,true |
| e. | Prints: true,false,false |
| f. | Prints: true,false,true |
| g. | Prints: true,true,false |
| h. | Prints: true,true,true |
| i. | None of the above |
Question 5
| | • | Entries are organized as key/value pairs. |
| | • | Duplicate entries replace old entries. |
Which interface of the java.util package
offers the specified behavior?
| a. | List |
| b. | Map |
| c. | Set |
| d. | None of the above |
Question 6
import java.util.*;
class GFC102 {
public static void main (String args[]) {
Object a = new HashSet();
System.out.print((a instanceof Set)+",");
System.out.print(a instanceof SortedSet);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false |
| b. | Prints: false,true |
| c. | Prints: true,false |
| d. | Prints: true,true |
| e. | None of the above |
Question 7
Which implementation of the List interface provides for the
fastest insertion of a new element into the middle of the list?
| a. | Vector |
| b. | ArrayList |
| c. | LinkedList |
| d. | None of the above |
Question 8
import java.util.*;
class GFC103 {
public static void main (String args[]) {
Object a1 = new TreeSet();
System.out.print((a1 instanceof Set)+",");
System.out.print(a1 instanceof SortedSet);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false |
| b. | Prints: false,true |
| c. | Prints: true,false |
| d. | Prints: true,true |
| e. | None of the above |
Question 9
| | • | Stores key/value pairs. |
| | • | Duplicate entries replace old entries. |
| | • | Entries are sorted using a Comparator or the Comparable interface. |
Which of these classes provides the specified features?
| a. | LinkedList |
| b. | TreeMap |
| c. | TreeSet |
| d. | HashMap |
| e. | HashSet |
| f. | Hashtable |
| g. | None of the above |
Question 10
import java.util.*;
class GFC104 {
public static void main (String args[]) {
LinkedList a1 = new LinkedList();
ArrayList b1 = new ArrayList();
Vector c1 = new Vector();
System.out.print((a1 instanceof List)+",");
System.out.print((b1 instanceof List)+",");
System.out.print(c1 instanceof List);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false,false |
| b. | Prints: false,false,true |
| c. | Prints: false,true,false |
| d. | Prints: false,true,true |
| e. | Prints: true,false,false |
| f. | Prints: true,false,true |
| g. | Prints: true,true,false |
| h. | Prints: true,true,true |
| i. | None of the above |
Question 11
| | • | Entries are not organized as key/value pairs. |
| | • | Duplicate entries are rejected. |
Which interface of the java.util package
offers the specified behavior?
| a. | List |
| b. | Map |
| c. | Set |
| d. | None of the above |
Question 12
import java.util.*;
class GFC105 {
public static void main (String args[]) {
Object a = new HashSet(), b = new HashMap();
Object c = new Hashtable();
System.out.print((a instanceof Collection)+",");
System.out.print((b instanceof Collection)+",");
System.out.print(c instanceof Collection);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false,false |
| b. | Prints: false,false,true |
| c. | Prints: false,true,false |
| d. | Prints: false,true,true |
| e. | Prints: true,false,false |
| f. | Prints: true,false,true |
| g. | Prints: true,true,false |
| h. | Prints: true,true,true |
| i. | None of the above |
Question 13
| | • | Elements are not key/value pairs. |
| | • | Contains no duplicate elements. |
| | • | The entries can be sorted using the Comparable interface. |
Which of these classes provides the specified features?
| a. | LinkedList |
| b. | TreeMap |
| c. | TreeSet |
| d. | HashMap |
| e. | HashSet |
| f. | Hashtable |
| g. | None of the above |
Question 14
import java.util.*;
class GFC106 {
public static void main (String args[]) {
Object a = new HashSet(), b = new HashMap();
Object c = new Hashtable();
System.out.print((a instanceof Map)+",");
System.out.print((b instanceof Map)+",");
System.out.print(c instanceof Map);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false,false |
| b. | Prints: false,false,true |
| c. | Prints: false,true,false |
| d. | Prints: false,true,true |
| e. | Prints: true,false,false |
| f. | Prints: true,false,true |
| g. | Prints: true,true,false |
| h. | Prints: true,true,true |
| i. | None of the above |
Question 15
| | • | Stores key/value pairs. |
| | • | Allows null elements, keys, and values. |
| | • | Duplicate entries replace old entries. |
| | • | Entries are not sorted. |
Which of these classes provides the specified features?
| a. | LinkedList |
| b. | TreeMap |
| c. | TreeSet |
| d. | HashMap |
| e. | HashSet |
| f. | Hashtable |
| g. | None of the above |
Question 16
import java.util.*;
class GFC107 {
public static void main (String args[]) {
Object a = new HashSet(), b = new HashMap();
Object c = new Hashtable();
System.out.print((a instanceof Cloneable)+",");
System.out.print((b instanceof Cloneable)+",");
System.out.print(c instanceof Cloneable);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false,false |
| b. | Prints: false,false,true |
| c. | Prints: false,true,false |
| d. | Prints: false,true,true |
| e. | Prints: true,false,false |
| f. | Prints: true,false,true |
| g. | Prints: true,true,false |
| h. | Prints: true,true,true |
| i. | None of the above |
Question 17
| | • | Entries are not organized as key/value pairs. |
| | • | Generally accepts duplicate elements. |
| | • | Entries may be accessed by means of an index. |
Which interface of the java.util package
offers the specified behavior?
| a. | List |
| b. | Map |
| c. | Set |
| d. | None of the above |
Question 18
import java.util.*;
import java.io.Serializable;
class GFC108 {
public static void main (String args[]) {
HashMap a = new HashMap();
boolean b1, b2, b3;
b1 = (a instanceof Cloneable) & (a instanceof Serializable);
b2 = a instanceof Map;
b3 = a instanceof Collection;
System.out.print(b1 + "," + b2 + "," + b3);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false,false |
| b. | Prints: false,false,true |
| c. | Prints: false,true,false |
| d. | Prints: false,true,true |
| e. | Prints: true,false,false |
| f. | Prints: true,false,true |
| g. | Prints: true,true,false |
| h. | Prints: true,true,true |
| i. | None of the above |
Question 19
Which of the following classes allow unsynchronized
read operations by multiple threads?
| a. | Vector |
| b. | Hashtable |
| c. | TreeMap |
| d. | TreeSet |
| e. | HashMap |
| f. | HashSet |
Question 20
| | • | Entries are organized as key/value pairs. |
| | • | Duplicate entries replace old entries. |
| | • | Entries are sorted using a Comparator or the Comparable interface. |
Which interface of the java.util package
offers the specified behavior?
| a. | List |
| b. | Map |
| c. | Set |
| d. | SortedSet |
| e. | SortedMap |
| f. | None of the above |
Question 21
import java.util.*;
class GFC110 {
public static void main (String[] args) {
Object m = new LinkedHashMap();
System.out.print((m instanceof Collection)+",");
System.out.print((m instanceof Map)+",");
System.out.print(m instanceof List);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false,false |
| b. | Prints: false,false,true |
| c. | Prints: false,true,false |
| d. | Prints: false,true,true |
| e. | Prints: true,false,false |
| f. | Prints: true,false,true |
| g. | Prints: true,true,false |
| h. | Prints: true,true,true |
| i. | None of the above |
Question 22
import java.util.*;
class GFC109 {
public static void main (String[] args) {
Object v = new Vector();
System.out.print((v instanceof Collections)+",");
System.out.print((v instanceof Arrays)+",");
System.out.print(v instanceof List);
}}
What is the result of attempting to compile and run the program?
| a. | Prints: false,false,false |
| b. | Prints: false,false,true |
| c. | Prints: false,true,false |
| d. | Prints: false,true,true |
| e. | Prints: true,false,false |
| f. | Prints: true,false,true |
| g. | Prints: true,true,false |
| h. | Prints: true,true,true |
| i. | None of the above |
Copyright © 2002-2004, Dan Chisholm
All rights reserved.