Question 1

The String class's __________ method accepts a value of any primitive data type as its argument and returns a string representation of the value.
A) trim
B) getChar
C) toString
D) valueOf

Accepted Answer

The valueOf method accepts a value of any primitive data type as its argument and returns a string representation of the value. The trim method removes leading and trailing white spaces from a string. The getChar method is not a valid method in the String class. The toString method returns a string representation of an object.

Question 2

What will be displayed after the following statements are executed? 
String str = "red$green&blue#orange";
String[] tokens = str.split("[$&#]");
For (String s : tokens)
System.out.print(s + " ");
A) red green blue orange
B) red $ green & blue # orange
C) $ & #
D) red[$&#]green[$&#]blue[$&#]orange

Accepted Answer

The split() method splits the string based on the given regular expression. In this case, the regular expression specifies three different delimiters: $, & and #. Therefore, the resulting tokens will be "red", "green", "blue", and "orange". The for loop simply prints out each token with a space separating them.

Question 3

The __________ class is the wrapper class for the char data type.
A) StringBuilder
B) Integer
C) Character
D) String

Accepted Answer

The Character class is the wrapper class for the char data type. It provides various methods to manipulate and convert between characters and strings. The StringBuilder class is for manipulating strings, the Integer class is for wrapping integers, and the String class is for representing strings, but not specifically for wrapping the char data type.

Question 4

Which of the following statements is not true about the following code? StringBuilder strb = new StringBuilder("Total number of parts: ");
Strb.insert(23, 32);
A) The starting position for the insert is 23.
B) strb is a StringBuilder type object.
C) The ending position for the insert is 32.
D) The literal number 32 will be inserted into the string.

Accepted Answer

The statement C is not true because the insert method of StringBuilder does not have a concept of an "ending position" for the insert operation. Instead, it inserts the specified data (in this case, the number 32) at the specified position (23 in this case), directly into the StringBuilder object.

Question 5

What will be the value of position after the following code is executed? int position;
String str = "The cow jumped over the moon.";
Position = str.indexOf("ov");
A) 14
B) 15
C) 18
D) 17

Accepted Answer

The indexOf() method returns the index of the first occurrence of the specified substring. In this case, "ov" first occurs at index 15 (counting starts at 0), so the value of position will be 15.

Question 6

In the following statement, what data type must recField be? str.getChars(5, 10, recField, 0);
A) int
B) char[]
C) char
D) String

Accepted Answer

The method str.getChars() gets a range of characters from a String and stores it in a char array. Therefore, the data type of recField must be a char array (represented as char[] in Java) to store the characters retrieved from the String.

Question 7

What will be the value of position after the following code is executed? int position;
String str = "The cow jumped over the moon.";
Position = str.lastIndexOf("ov", 14);
A) 14
B) 1
C) 0
D) -1

Accepted Answer

The method lastIndexOf(String str, int fromIndex) searches for the last occurrence of a substring within the given string, starting the search at the specified index and moving backwards. It returns -1 if the substring is not found. In this case, "ov" does not occur before or at index 14 in the string "The cow jumped over the moon.", so the method returns -1.

Question 8

The StringBuilder class's insert method allows you to insert a(n) __________ into the calling object's string.
A) char array
B) primitive type
C) String object
D) All of these

Accepted Answer

The insert method of StringBuilder class allows you to insert a char array, primitive type, or a String object into the calling object's string. Therefore, the best choice is D (All of these).

Question 9

What are the tokens in the following statement? 
StringTokenizer st = new StringTokenizer("9-14-2018", "-", true);
A) 9, 14, 2018
B) 9, 14, 2018, and -
C) -
D) None of these

Accepted Answer

The StringTokenizer class in Java is used to break a string into tokens. Here, "9-14-2018" is the string to be tokenized, "-" is the delimiter, and the 'true' flag indicates that the delimiter itself should be returned as a token. Therefore, the tokens are "9", "-", "14", "-", "2018".

Question 10

You can concatenate String objects by using the
A) concat or trim methods
B) concat method or the + operator
C) concatenate or join methods
D) concatenate method or the + operator

Accepted Answer

The concat method is one option to concatenate String objects, but using the + operator is a more commonly used and convenient method. The trim method is used to remove whitespace from the beginning and end of a String, and the concatenate and join methods are not valid methods for String concatenation.

Question 11

Which of the following is(are) used as delimiters if the StringTokenizer class's constructor is called and a reference to a String object is passed as the only argument?
A) space
B) tab
C) newline
D) All of these

Accepted Answer

The StringTokenizer class, when called with a single String argument, uses space, tab, and newline as default delimiters.

Question 12

What will be displayed after the following code is executed? 
String str = "abc456";
For (int i = 0; i < str.length(); i++)
{
Char chr = str.CharAt(i);
If (!Character.isLetter(chr))
System.out.print(Character.toUpperCase(chr));
}
A) ABC
B) ABC456
C) 456
D) abc456

Accepted Answer

The code goes through each character in the string using a for loop. It checks if the character is not a letter using the Character.isLetter() method. If it is not a letter, it prints the uppercase version of the character using the Character.toUpperCase() method. In this case, the characters that are not letters are '4', '5', and '6', so the output is "456".

Question 13

Any ___________ argument passed to the Character class's toLowerCase method or toUpperCase method is returned as it is.
A) nonletter
B) char
C) string
D) static

Accepted Answer

The toLowerCase and toUpperCase methods are only concerned with converting alphabetic characters to their lowercase or uppercase equivalents. Any non-alphabetic character passed as an argument will be returned as it is. Therefore, the best choice for the blank is "nonletter" (option A).

Question 14

What will be displayed after the following statements are executed? 
StringBuilder strb = new StringBuilder("We have lived in Chicago, Trenton, and Atlanta.");
Strb.replace(17, 24, "Tampa");
System.out.println(strb);
A) We have lived in Tampa, Trenton, and Atlanta.
B) We have lived in Chicago, Trenton, and Tampa.
C) We have lived in Chicago,Tampaon, and Atlanta.
D) We have lived in Chicago, Tampa, and Atlanta.

Accepted Answer

The `replace` method of `StringBuilder` replaces the text within the specified range with the new text. The range starts at index 17 and ends at index 24, which corresponds to "Chicago" in the original string. Replacing "Chicago" with "Tampa" results in the string "We have lived in Tampa, Trenton, and Atlanta."

Question 15

Given the following code, how many times will the while loop be executed? StringTokenizer st = new StringTokenizer("Java programming is fun!");
While (st.hasMoreTokens())
System.out.println(st.nextToken());
A) 7
B) 4
C) 5
D) 1

Accepted Answer

The StringTokenizer will split the string "Java programming is fun!" into tokens based on the default delimiters (which include spaces, tabs, newlines, carriage returns, and form feeds), resulting in 4 tokens: "Java", "programming", "is", "fun!". Therefore, the loop will be executed 4 times, once for each token.

Question 16

What will be displayed after the following code is executed? 
boolean matches;
String str1 = "The cow jumped over the moon.";
String str2 = "moon";
Matches = str1.endsWith(str1);
System.out.println(matches);
A) true
B) moon
C) false
D) The cow

Accepted Answer

The variable "matches" is being assigned the result of comparing whether the string "str1" ends with the same string "str1" itself, which is not possible. Therefore, the value of "matches" will be false. The output of the code will be "false".

Question 17

The Character wrapper class provides numerous methods for
A) converting objects to primitive data types
B) testing and converting character data
C) testing and converting numeric literals
D) performing operations with named constants

Accepted Answer

The Character wrapper class provides methods for testing and converting character data, such as isLetter(), isDigit(), toLowerCase(), and toUpperCase(). It does not provide methods for converting objects to primitive data types or performing operations with named constants like the other wrapper classes do.

Question 18

What will be displayed after the following code is executed? 
StringBuilder strb = new StringBuilder(12);
Strb.append("The cow ");
Strb.append("jumped over the ");
Strb.append("moon.");
System.out.println(strb);
A) The cow
Jumped over the
Moon.
B) The cow jumped over the moon.
C) The cow jump
D) 12The cow jumped over the moon.

Accepted Answer

The code creates a StringBuilder object with a capacity of 12 characters. Then, it appends the strings "The cow", "jumped over the", and "moon." to the StringBuilder object using the append() method. Finally, it prints the contents of the StringBuilder object using the println() method. Since all three strings were appended to the StringBuilder object, the output will be "The cow jumped over the moon."

Question 19

What will be displayed after the following code is executed? 
String str1 = "The quick brown fox jumped over the lazy dog.";
String str2 = str1.substring(20, 26);
System.out.println(str2);
A) n fox
B) jumped
C) lazy d
D) x jump

Accepted Answer

The substring method in Java is zero-based and the call str1.substring(20, 26) extracts the characters from index 20 to 25 (the character at index 26 is not included), which corresponds to the word "jumped".

Question 20

What will be displayed after the following code is executed? 
String str = "RSTUVWXYZ";
System.out.println(str.charAt(5));
A) W
B) X
C) V
D) U

Accepted Answer

The charAt method returns the character at a specific index in a string, starting from 0. Therefore, str.charAt(5) returns the character at index 5, which is 'W'.

Quiz 8: Text Processing and Wrapper Classes

The String class's __________ method accepts a value of any primitive data type as its argument and returns a string representation of the value.

What will be displayed after the following statements are executed? String str = "red$green&blue#orange"; String[] tokens = str.split("[$&#]") ; For (String s : tokens) System.out.print(s + " ") ;

The __________ class is the wrapper class for the char data type.

Which of the following statements is not true about the following code? StringBuilder strb = new StringBuilder("Total number of parts: ") ; Strb.insert(23, 32) ;

What will be the value of position after the following code is executed? int position; String str = "The cow jumped over the moon."; Position = str.indexOf("ov") ;

In the following statement, what data type must recField be? str.getChars(5, 10, recField, 0) ;

What will be the value of position after the following code is executed? int position; String str = "The cow jumped over the moon."; Position = str.lastIndexOf("ov", 14) ;

The StringBuilder class's insert method allows you to insert a(n) __________ into the calling object's string.

What are the tokens in the following statement? StringTokenizer st = new StringTokenizer("9-14-2018", "-", true) ;

You can concatenate String objects by using the

Which of the following is(are) used as delimiters if the StringTokenizer class's constructor is called and a reference to a String object is passed as the only argument?

What will be displayed after the following code is executed? String str = "abc456"; For (int i = 0; i < str.length() ; i++) { Char chr = str.CharAt(i) ; If (!Character.isLetter(chr) ) System.out.print(Character.toUpperCase(chr) ) ; }

Any ___________ argument passed to the Character class's toLowerCase method or toUpperCase method is returned as it is.

What will be displayed after the following statements are executed? StringBuilder strb = new StringBuilder("We have lived in Chicago, Trenton, and Atlanta.") ; Strb.replace(17, 24, "Tampa") ; System.out.println(strb) ;

Given the following code, how many times will the while loop be executed? StringTokenizer st = new StringTokenizer("Java programming is fun!") ; While (st.hasMoreTokens() ) System.out.println(st.nextToken() ) ;

What will be displayed after the following code is executed? boolean matches; String str1 = "The cow jumped over the moon."; String str2 = "moon"; Matches = str1.endsWith(str1) ; System.out.println(matches) ;

The Character wrapper class provides numerous methods for

What will be displayed after the following code is executed? StringBuilder strb = new StringBuilder(12) ; Strb.append("The cow ") ; Strb.append("jumped over the ") ; Strb.append("moon.") ; System.out.println(strb) ;

What will be displayed after the following code is executed? String str1 = "The quick brown fox jumped over the lazy dog."; String str2 = str1.substring(20, 26) ; System.out.println(str2) ;

What will be displayed after the following code is executed? String str = "RSTUVWXYZ"; System.out.println(str.charAt(5) ) ;