Question 1

What would be the results of executing the following code? StringBuilder str = new StringBuilder(12);
Str)append("The cow");
Str)append(" jumped over the ");
Str)append("moon.");
A) The program would crash
B) str would reference "The cow jump"
C) str would reference "The cow jumped over the "
D) str would reference "The cow jumped over the moon."

Accepted Answer

The StringBuilder object named "str" is created with an initial capacity of 12 characters. Then, three append() methods are called subsequently to add strings to the StringBuilder object. This code does not contain any syntax errors, so the program would not crash. The final result of the code would be that the StringBuilder object "str" will reference a string that says "The cow jumped over the moon."

Question 2

Look at the following code. Integer myNumber = new Integer(5);
Int var = myNumber;
Which of the following is true about the second statement?
A) It results in an error because you cannot assign a wrapper class object to a primitive variable.
B) The statement performs autoboxing.
C) The statement performs unboxing.
D) The statement performs unwrapping.

Accepted Answer

The statement performs unboxing, which means that the Integer object is automatically converted to its corresponding primitive type, in this case, int. Therefore, the variable var is assigned the value 5, which is the value of the Integer object.

Question 3

Look at the following code. Integer myNumber;
MyNumber = 5;
Which of the following is true about the second statement?
A) It results in an error because you cannot assign a primitive type to a wrapper class object.
B) The statement performs autoboxing.
C) The statement performs unboxing.
D) The statement performs autowrapping.

Accepted Answer

The second statement performs autoboxing, which is the automatic conversion of a primitive type to its corresponding wrapper class object. In this case, the integer value 5 is automatically converted to an Integer object, which is then assigned to the variable MyNumber.

Question 4

What does the following statement do? Float number = new Float(8.8);
A) It creates a Float object
B) It initializes that object to 8.8
C) It assigns the object's address to the number variable
D) All of the above

Accepted Answer

The statement creates a Float object using the constructor method and initializes it to the value 8.8, then assigns the object's address to the variable "number". So, all three options are correct.

Question 5

Given the following statement,which of the following is not true? str.insert(8,32);
A) str is a StringBuilder type object
B) The insert will start at position 32
C) The starting position for the insert is 8
D) The literal number 32 will be inserted

Accepted Answer

The number 32 in the statement actually represents a space character, not a position. So, the insert will start at position 8 and a space character will be inserted.

Question 6

What will be the tokens in the following statement? String str = "red$green&blue#orange";
String tokens = str.split("[$&#]");
A) "red","green","blue"and "orange"
B) "$","&",and "#"
C) "[","$","&","#",and "]"
D) None of the above

Accepted Answer

The split method splits the string into an array of substrings based on the specified delimiter. In this case, the delimiter is a character class containing the special characters $, &, and #. Therefore, the resulting tokens will be "red", "green", "blue", and "orange". Option B is incorrect because the split method removes the delimiter characters and only returns the substrings. Option C is incorrect because the character "[" is not included in the delimiter character class and therefore will not be used as a delimiter. Option D is incorrect because the correct answer is A.

Question 7

What will be printed after the following code is executed? String str = "abc456";
Int m = 0;
While ( m < 6 )
{
If (!Character.isLetter(str.charAt(m)))
System.out.print(
Character.toUpperCase(str.charAt(m)));
M++;
}
A) 456
B) ABC456
C) ABC
D) abc456

Accepted Answer

The code will iterate through each character in the string "abc456" and check if it is not a letter (using the Character.isLetter() method). If the character is not a letter, it will print the uppercase version of that character. Therefore, the code will print "456" because those are the non-letter characters in the string. The other characters ("abc") are not printed because they are letters.

Question 8

For the following code,how many times would the while loop execute? StringTokenizer strToken =
New StringTokenizer("Ben and Jerry's ice cream is great.");
While (strToken.hasMoreTokens())
{
System.out.println(strToken.nextToken());
}
A) 1
B) 3
C) 5
D) 7

Accepted Answer

The StringTokenizer will split the string "Ben and Jerry's ice cream is great." into 7 tokens: "Ben", "and", "Jerry's", "ice", "cream", "is", "great". The while loop will execute once for each token, totaling 7 times.

Question 9

If you do not specify delimiters in the StringToken constructor,which of the following cannot be a delimiter?
A) Space
B) Tab
C) Semicolon
D) Newline

Accepted Answer

By default, the StringTokenizer class uses whitespace characters (space, tab, newline) as delimiters. Semicolon is not a default delimiter.

Question 10

What is the value of str after the following code has been executed? String str;
String sourceStr = "Hey diddle,diddle,the cat and the fiddle";
Str = sourceStr.substring(12,17);
A) diddle
B) diddl
C) ,didd
D) Iddle

Accepted Answer

The answer of What is the value of str after...

Question 11

In a string that contains a series of words or other items of data separated by spaces or other characters,the programming term for the data items is
A) token
B) delimiter
C) buffer
D) separator

Accepted Answer

In programming, a data item in a string that is separated by spaces or other characters is known as a token.

Question 12

What will be the value of matches after the following code has been executed? boolean matches;
String str1 = "The cow jumped over the moon.";
String str2 = "moon";
Matches = str1.endsWith(str2);
A) true
B) false
C) moon
D) The cow

Accepted Answer

The answer of What will be the value of matches...

Question 13

What will be the value of loc after the following code is executed? int loc;
String str = "The cow jumped over the moon.";
Loc = str.lastIndexOf("ov",14);
A) 15
B) 16
C) 0
D) -1

Accepted Answer

The method lastIndexOf("ov", 14) searches for the last occurrence of "ov" in the substring of str from the beginning to index 14. There is no "ov" in that range, so it returns -1.

Question 14

What will be the tokens in the following statement? StringTokenizer strToken =
New StringTokenizer("January 1,2008",",",true);
A) The tokens will be:
January,1
2008
B) The tokens will be
,
Space
C) The tokens will be:
January
1
2008
Space
D) The tokens will be:
January
Space
1
,
Space
2008

Accepted Answer

The StringTokenizer is initialized with the string "January 1,2008" and the delimiter "," with the flag set to true, meaning the delimiter will also be returned as a token. The tokens will be: "January", " ", "1", ",", "2008".

Question 15

Two ways of concatenating two Strings are
A) Use the concat()method or use the + between the two Strings
B) Use the concatenate()method or use the + between the two Strings
C) Use the contenate()method or the concat()method
D) Use the concat()method or the trim()method

Accepted Answer

Both the concat() method and + operator can be used to concatenate two Strings. However, using the + operator is more convenient and readable in most scenarios. Therefore, the best choice is to use the + operator between the two Strings.

Question 16

Which of the following statements will print the maximum value an int variable may have?
A) System.out.println(MAX_VALUE);
B) System.out.println(integer.MAX_VALUE);
C) System.out.println(Integer.MAX_VALUE);
D) System.out.println(INTEGER.MAX_VALUE);

Accepted Answer

The correct statement to print the maximum value of an int variable is Integer.MAX_VALUE, as MAX_VALUE is a static field in the Integer class that contains the maximum value an int can have. Options A and D are incorrect due to incorrect syntax and capitalization, while option B is incorrect as the Integer class needs to be explicitly referenced.

Question 17

The no-arg constructor for a StringBuilder object gives the object enough storage space to hold this many characters.
A) 0 characters
B) 8 characters
C) 16 characters
D) 32 characters

Accepted Answer

The no-arg constructor for a StringBuilder object gives the object enough storage space to hold 16 characters.

Question 18

If str is declared as String str = "ABCDEFGHI";
What will be returned from Character.toLowerCase(str.charAt(5))?
A) e
B) E
C) f
D) F

Accepted Answer

The answer of If str is declared as String str...

Question 19

If a non-letter is passed to the toLowerCase or toUpperCase method,it is returned unchanged.

Accepted Answer

This is correct, as the methods only affect letters and leave non-letters unchanged.

Question 20

To convert the string,str = "285" to an int,use the following statement
A) int x = str;
B) int x = Integer.parseInteger(str);
C) int x = Integer.integer(str);
D) int x = Integer.parseInt(str);

Accepted Answer

The correct method to convert a string to an integer in Java is to use the parseInt() method of the Integer class. This method takes a string as an argument and returns an integer representing the value of that string. Therefore, the correct statement to convert the given string, "285", to an integer is:

int x = Integer.parseInt(str);

Quiz 10: Text Processing and More About Wrapper Classes

What would be the results of executing the following code? StringBuilder str = new StringBuilder(12) ; Str) append("The cow") ; Str) append(" jumped over the ") ; Str) append("moon.") ;

Look at the following code. Integer myNumber = new Integer(5) ; Int var = myNumber; Which of the following is true about the second statement?

Look at the following code. Integer myNumber; MyNumber = 5; Which of the following is true about the second statement?

What does the following statement do? Float number = new Float(8.8) ;

Given the following statement,which of the following is not true? str.insert(8,32) ;

What will be the tokens in the following statement? String str = "red$green&blue#orange"; String tokens = str.split("[$&#]") ;

What will be printed after the following code is executed? String str = "abc456"; Int m = 0; While ( m < 6 ) { If (!Character.isLetter(str.charAt(m) ) ) System.out.print( Character.toUpperCase(str.charAt(m) ) ) ; M++; }

For the following code,how many times would the while loop execute? StringTokenizer strToken = New StringTokenizer("Ben and Jerry's ice cream is great.") ; While (strToken.hasMoreTokens() ) { System.out.println(strToken.nextToken() ) ; }

If you do not specify delimiters in the StringToken constructor,which of the following cannot be a delimiter?

What is the value of str after the following code has been executed? String str; String sourceStr = "Hey diddle,diddle,the cat and the fiddle"; Str = sourceStr.substring(12,17) ;

In a string that contains a series of words or other items of data separated by spaces or other characters,the programming term for the data items is

What will be the value of matches after the following code has been executed? boolean matches; String str1 = "The cow jumped over the moon."; String str2 = "moon"; Matches = str1.endsWith(str2) ;

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

What will be the tokens in the following statement? StringTokenizer strToken = New StringTokenizer("January 1,2008",",",true) ;

Two ways of concatenating two Strings are

Which of the following statements will print the maximum value an int variable may have?

The no-arg constructor for a StringBuilder object gives the object enough storage space to hold this many characters.

If str is declared as String str = "ABCDEFGHI"; What will be returned from Character.toLowerCase(str.charAt(5) ) ?

If a non-letter is passed to the toLowerCase or toUpperCase method,it is returned unchanged.

To convert the string,str = "285" to an int,use the following statement