Question 1

For the following code, how many times would the for loop execute?
String str = "1,2,3,4,5,6,7,8,9");
String[] tokens = str.split(",");
For (String s : tokens)
System.out.println(s);
A) 1
B) 5
C) 7
D) 9

Accepted Answer

The for loop will execute 9 times, once for each token in the "tokens" array created by splitting the string at every comma.

Question 2

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 creates an empty string builder with an initial capacity of 16 characters.

Question 3

This is the process of converting a wrapper class object to a primitive type.
A) simplifying
B) unboxing
C) parsing
D) devaluating

Accepted Answer

Unboxing is the process of converting an object of a wrapper class to its corresponding primitive type. For example, converting an Integer object to int.

Question 4

Each of the numeric wrapper classes has a static ________ method that converts a number to a string.
A) GetString
B) Parse
C) ToString
D) Convert

Accepted Answer

The ToString() method is used to convert a number to a string in each of the numeric wrapper classes such as Integer, Double, Float, etc. This method is static and can be called directly on the class without creating an instance.

Question 5

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 is initialized with a capacity of 12 characters. The three append statements add a total of 29 characters to the StringBuilder object. Therefore, str would reference "The cow jumped over the moon."

Question 6

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 7

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 parameters for the insert method in StringBuilder are (int index, Object obj), where index is the starting position and obj is the object to be inserted. Therefore, in the statement str.insert(8, 32), the insert will start at index 8 and the object being inserted is the int value 32.

Question 8

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

Option A is correct because the concat() method and + operator can be used to concatenate two Strings. The concatenate() method is not a valid method for concatenating Strings in Java. The trim() method is used for removing white spaces from the beginning and end of a String, and is not related to concatenating Strings.

Question 9

For the following code, how many times would the for loop execute?
String str = ("Ben and Jerry's ice cream is great.");
String[] tokens = str.split(" ");
For (String s : tokens)
System.out.println(s);
A) 1
B) 3
C) 5
D) 7

Accepted Answer

The string is split into tokens based on spaces, resulting in 7 tokens: "Ben", "and", "Jerry's", "ice", "cream", "is", "great.".

Question 10

What will be the tokens given the following statements?
String str = ("January 1, 2016");
String[] tokens = str.split(" ");
A) The tokens will be: January
1,
2016
B) The tokens will be: ,
Space
C) The tokens will be: January
1
2016
Space
D) The tokens will be: January
Space
1
,
Space
2016

Accepted Answer

The split() method splits a string into an array of strings by the delimiter specified in the argument. In this case, the delimiter is " ", which is a space character. Therefore, the tokens will be split at each space character. The resulting array of strings will contain the following elements: "January", "1", "2016".

Question 11

When using the String class's trim method, which of the following cannot be trimmed?
A) Space
B) Tab
C) Semicolon
D) Newline

Accepted Answer

The String class's trim method only trims whitespace characters, such as spaces and tabs. Semicolons are not considered whitespace characters and therefore cannot be trimmed using the trim method.

Question 12

To convert the string, str = "285.74" to a double, use the following statement:
A) double x = str;
B) double x = Double.parseDouble(str);
C) double x = Double.Double(str);
D) double x = str,Double.parseDouble;

Accepted Answer

The correct statement to convert a string into a double is Double.parseDouble(str). This method parses the string argument as a double and returns the value represented by the string.

Question 13

Use the following import statement when using the Character wrapper class:
A) import java.Char
B) import java.lang.Char
C) import java.String
D) No import statement is needed

Accepted Answer

No import statement is needed because the Character class is part of the java.lang package, which is automatically imported into every Java program.

Question 14

What does the following statement do?
Double number = new Double(8.8);
A) It creates a Double 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 Double object, initializes it to 8.8, and assigns the object's address to the number variable. Therefore, all three options are correct.

Question 15

Which of the following statements will print the maximum value a double variable may have?
A) System.out.println(MAX_VALUE);
B) System.out.println(double.MAX_VALUE);
C) System.out.println(Double.MAX_VALUE);
D) System.out.println(Double.MAXIMUM_VALUE);

Accepted Answer

The correct syntax to print the maximum value of a double variable is Double.MAX_VALUE. Therefore, option C is the correct choice. Options A, B, and D are incorrect because they either have wrong syntax or do not refer to the correct constant.

Question 16

To convert the int variable, number to a string, use the following statement:
A) String str = Integer.toString(number);
B) String str = integer.toString(number);
C) String str = integer(number);
D) String str = number.Integer.toString(str);

Accepted Answer

The correct syntax to convert an int variable to a string is to use the static method Integer.toString(). This converts the int value to a String object. Therefore, option A is the correct choice. Option B is incorrect because integer should be capitalized as it is a class name, not a variable. Option C is incorrect because integer is not a valid method in Java. Option D is incorrect because the syntax is incorrect and the logic is backwards.

Question 17

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 execute a while loop that will run as long as the value of m is less than 6. Inside the loop, an if statement checks whether the character at index m of the string is not a letter. If it is not a letter, the if statement will print the uppercase version of that character. Afterward, the value of m will be incremented by one. Therefore, the output will be 456 since only the numeric characters will be printed in uppercase.

Question 18

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 19

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 `lastIndexOf` method searches for the last occurrence of the specified substring ("ov") within the string up to the specified index (14). Since "ov" appears at index 19 in the string and not before index 14, the method returns -1.

Question 20

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...

Quiz 9: Text Processing and More About Wrapper Classes

For the following code, how many times would the for loop execute? String str = "1,2,3,4,5,6,7,8,9") ; String[] tokens = str.split(",") ; For (String s : tokens) System.out.println(s) ;

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

This is the process of converting a wrapper class object to a primitive type.

Each of the numeric wrapper classes has a static ________ method that converts a number to a string.

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.") ;

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

Given the following statement, which of the following is NOT true? Str) insert(8, 32) ;

Two ways of concatenating two Strings are:

For the following code, how many times would the for loop execute? String str = ("Ben and Jerry's ice cream is great.") ; String[] tokens = str.split(" ") ; For (String s : tokens) System.out.println(s) ;

What will be the tokens given the following statements? String str = ("January 1, 2016") ; String[] tokens = str.split(" ") ;

When using the String class's trim method, which of the following cannot be trimmed?

To convert the string, str = "285.74" to a double, use the following statement:

Use the following import statement when using the Character wrapper class:

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

Which of the following statements will print the maximum value a double variable may have?

To convert the int variable, number to a string, use the following statement:

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++; }

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 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) ;