Chapter 7

Question 1

What is each created string?

Answer 1

A class object

Question 2

What happens when you use “==” with strings?

Answer 2

Comparing computer memory locations, not their values

Question 3

What is a literal string?

Answer 3

• A sequence of characters enclosed within double quotation marks
• An unnamed object, or anonymous object, of the string class

Question 4

What is a string variable?

Answer 4

• A named object of the string class
• A reference variable
• Refers to a location in memory rather then to a particular value

Question 5

What happens when you try to assign a new value to a String?

Answer 5

• The adress held by the string is altered

Question 6

What are immutable objects?

Answer 6

• Objects taht cannot be changed, such as a String
• After a string is created, it is Immutable

Question 7

What is the Equals() method?

Answer 7

• Returns the content of the two String objects to determine if they are equivalent

Question 8

What is the equalsIgnoreCase() method?

Answer 8

• Ignore case when determining if two strings are equivilant

Question 9

What is the compareto() method?

Answer 9

• Compares two Strings and returns:
• Zero: if the two strings refer to the same value
• Negative Number: if the calling object is “less than” the argument
• Positive number: “If the calling object is “more than” the argument

Question 10

What are empty strings?

Answer 10

• Reference a memory adress with no characters
• Can be used in string methods

Question 11

What are null strings?

Answer 11

• Use the null java keyword
• Strings are set to null by default
• Cannot be used in String methods

Question 12

What are the toUpperCase() and toLowerCase() methods?

Answer 12

• Convert any styring to its uppercase or lowercase equivilant

Question 13

What is the Length() method?

Answer 13

Returns the length of a string?

Question 14

What is the indexOf() method?

Answer 14

• Determins weather a specific character occurs within a string
• Returns the position of the character
• The return value is -1 if the character does not exist in the String

Question 15

What is the charAt(0 method?

Answer 15

returns the character at the specified index in a string

Question 16

What is the endsWith() and startsWith() method

Answer 16

• Each takes a String argument
• Returns true of false if a String object does or does not start or end with the specified argument, respectively

Question 17

What is the -replace() method?

Answer 17

• Replaces all occurances of some character within a string

Question 18

What is the contains() method?

Answer 18

• Allows you to determine whether one string contains another
• Case sensitive

Question 19

What is the toString() method?

Answer 19

• Converts any object to a string
• Converts primitive data types to Strings

Question 20

What is the Substring() method?

Answer 20

• Extracts part of a String
• Takes two integer arguments: start and end position
• The length of the extracted substring is the difference between the second integer and the first integer

Question 21

What is the regionMatches() method?

Answer 21

• Two variants that can be used to test if two String regions are equal
• In one, a substrict of the specified String object is compared to the substring of the other
• If the substrings contain the same character sequence, then the expression is true, otherwise false
• Second version uses additional boolean argument to determine whether case is ignored when comparing characters

Question 22

What is the StringBUilder and StringBuffer classes?

Answer 22

• Alternative to string
• Used when a string will be modified
• Use anywhere you would use a string

Question 23

What are the differences between StringBuilder and StringBuffer classes?

Answer 23

• StringBuildeer = more efficient
• StringBuffer = Thread safe; used in multithreaded program

Question 24

What is a buffer?

Answer 24

• A memory block
• Might or might not contain a string
• The string might not occupy the entire buffer
• The length of a string can be different from the length of the buffer

Question 25

What is capacity?

Answer 25

The actual length of the buffer

Question 26

What is the append() method?

Answer 26

Adds characters to the end of a stringBuilder object

Question 27

What is the insert() method?

Answer 27

Adds characters at a specific location within a StringBuilder object

Question 28

What is the SetChar() method?

Answer 28

Changes a character at a specified position within a StringBuilder object