Question 1

The StringBuilder class's insert method allows you to insert into the calling object's string

Accepted Answer

The StringBuilder class's insert method allows you to insert a char array, a primitive type, or a String object into the calling object's string. Therefore, all of the above options are valid choices.

Question 2

Which of the following statements converts an int variable named number to a string and stores the value in the String object variable named str?

Accepted Answer

Option A uses the Integer class's static method toString() to convert the int variable "number" to a string, and then stores the string in a String object variable named "str".

Question 3

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));
}

Accepted Answer

The loop iterates through each character in the string, and for each character it checks if it is not a letter using the method `Character.isLetter()`. If it is not a letter, it prints out the uppercase version of that character using `Character.toUpperCase()`. So, in this case, only the characters '4', '5', and '6' are printed out, resulting in the output of "456".

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);

Accepted Answer

The ending position for the insert is not 32; 32 is the value being inserted into the StringBuilder at position 23.

Question 5

Which of the following statements converts a String object variable named str to an int and stores the value in the variable x?

Accepted Answer

To convert a String object variable to an int and store the value in a variable, we can use the Integer.parseInt() method. Option A is incorrect as it uses the wrong method name ("Integer.integer" instead of "Integer.parseInt"). Option B is incorrect as it tries to assign a String value to an int variable directly. Option C is incorrect as it uses the wrong method name ("parseInt" instead of "parseInteger").

Question 6

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

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'.

Question 7

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);

Accepted Answer

The replace() method replaces the characters in the specified range with the specified string. In this case, the characters from index 17 to 23 (inclusive) are replaced with the string "Tampa". Therefore, the output will be "We have lived in Tampa, Trenton, and Atlanta."

Question 8

Which of the following import statements is required to use the StringTokenizer class?

Accepted Answer

The StringTokenizer class is in the java.util package, so we need to import it using the import java.util.StringTokenizer statement. The other import statements are not relevant to using the StringTokenizer class.

Question 9

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);

Accepted Answer

The method `lastIndexOf("ov", 14)` searches for the last occurrence of "ov" in the substring of `str` that ends at index 14. The substring is "The cow jumped", which does not contain "ov", so it returns -1.

Question 10

A series of words or other items of data separated by spaces or other characters are known as

Accepted Answer

A series of words or other items of data separated by spaces or other characters are known as tokens. A string refers to a sequence of characters. Delimiters are the characters that separate tokens. Captions are titles or headings for images, tables, or other graphical elements.

Question 11

Which of the following 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?

Accepted Answer

If a reference to a String object is passed as the only argument in StringTokenizer class's constructor, then the default delimiters used are space, tab, and newline. Therefore, all of the above options are the correct choices.

Question 12

What will be the tokens in the following statement?
StringTokenizer st =
New StringTokenizer("9-14-2014", "-", true);

Accepted Answer

The StringTokenizer will split the input string "9-14-2014" into tokens using the delimiter "-", while keeping the delimiter as a separate token. Therefore, the resulting tokens will be 9, -, 14, -, 2014, which matches option B.

Question 13

Which of the following statements converts a double variable named tax to a string and stores the value in the String object variable named str?

Accepted Answer

The method Double.toString() can be used to convert a double variable to a string. We can then store the resulting string in a String object variable using the assignment operator ( = ). Therefore, option A is the correct answer. Option B is incorrect because "double" is a primitive data type and cannot be used as a method. Option C is incorrect because "double" is a primitive data type and cannot be used as an object. Option D is incorrect because the syntax is incorrect - "tax" should be the argument passed to the Double.toString() method, rather than "str".

Question 14

The Character wrapper class provides numerous methods for

Accepted Answer

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

Question 15

Which of the following statements will display the maximum value that a double can hold?

Accepted Answer

Double.MAX_VALUE is a constant in the Double class that represents the maximum value that a double can hold. Option B is incorrect because there is no such constant as Double.MAXIMUM_VALUE. Option C is incorrect because there is no such constant as Double.MAX_VAL. Option D is incorrect because <double> is not a valid syntax in Java and MAX_VALUE is a static constant of the Double class, so it doesn't need to be cast to double.

Question 16

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

Accepted Answer

The substring method of the String class returns a new string that is a substring of the original string. In this case, the substring method is called on str1 with parameters 20 and 26, so it returns a substring starting at index 20 (inclusive) and ending at index 26 (exclusive), which is "jumped". Therefore, the output of the code will be "jumped".

Question 17

For the following code, how many times would the while loop execute?
StringTokenizer st =
New StringTokenizer("Java programming is fun!");
While (st.hasMoreTokens())
System.out.println(st.nextToken());

Accepted Answer

The answer of For the following code, how many times...

Question 18

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

Accepted Answer

The getChars() method is used to extract characters from a String and store them in an array. Therefore, recField must be an array of characters (char[]).

Question 19

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

Accepted Answer

The answer of What will be displayed after the following...

Question 20

The ________ method returns a copy of the calling String object, in which all leading and trailing whitespace characters have been deleted.

Accepted Answer

The correct method to remove leading and trailing whitespace characters is the trim() method. Option A is incorrect because the remove() method is used to delete a specific substring from a string. Option C is incorrect because the compress() method is not a standard method for String objects in Java. Option D is incorrect because the concat() method is used to concatenate two or more string objects.

Quiz 8: Text Processing and Wrapper Classes

The StringBuilder class's insert method allows you to insert into the calling object's string

Which of the following statements converts an int variable named number to a string and stores the value in the String object variable named str?

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) ) ; }

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

Which of the following statements converts a String object variable named str to an int and stores the value in the variable x?

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

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) ;

Which of the following import statements is required to use the StringTokenizer class?

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 series of words or other items of data separated by spaces or other characters are known as

Which of the following 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 the tokens in the following statement? StringTokenizer st = New StringTokenizer("9-14-2014", "-", true) ;

Which of the following statements converts a double variable named tax to a string and stores the value in the String object variable named str?

The Character wrapper class provides numerous methods for

Which of the following statements will display the maximum value that a double can hold?

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

For the following code, how many times would the while loop execute? StringTokenizer st = New StringTokenizer("Java programming is fun!") ; While (st.hasMoreTokens() ) System.out.println(st.nextToken() ) ;

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

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

The ________ method returns a copy of the calling String object, in which all leading and trailing whitespace characters have been deleted.