Questions and Answers
Which class includes the methods isDigit, isLetter, and isLetterOrDigit?
What method converts a character to uppercase?
toUpperCase
Which class has the methods startsWith, endsWith, and regionMatches?
The indexOf and lastIndexOf methods are members of which class?
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Which of the following methods are members of the String class?
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What String class method performs the same operation as the + operator when used on strings?
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What is the name of the method that returns a string representation of a value from any primitive data type?
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If you do not pass an argument to the StringBuilder constructor, how many characters can it store?
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Which method is common to both the String and StringBuilder classes?
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What method is used to change the value of a specific character in a StringBuilder object?
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Which method is used to delete a specific character in a StringBuilder object?
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What is the term for the character that separates tokens in a string?
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Which String method breaks a string into tokens?
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What are the static final variables that hold the minimum and maximum values for numeric wrapper classes?
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Character testing methods, such as isLetter, accept strings as arguments and test each character in the string.
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If the toUpperCase method's argument is already uppercase, it is returned as is, with no changes.
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If the toLowerCase method's argument is already lowercase, it will be inadvertently converted to uppercase.
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The startsWith and endsWith methods are case-sensitive.
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There are two versions of the regionMatches method: one that is case-sensitive and one that can be case-insensitive.
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The indexOf and lastIndexOf methods can find characters, but cannot find substrings.
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The String class's replace method can replace individual characters, but cannot replace substrings.
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The StringBuilder class's replace method can replace individual characters, but cannot replace substrings.
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You can use the = operator to assign a string to a StringBuilder object.
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Study Notes
Character Methods
- Methods like isDigit, isLetter, and isLetterOrDigit belong to the Character class.
- The toUpperCase method is used to convert characters to uppercase.
String Class Methods
- The String class includes methods such as startsWith, endsWith, indexOf, lastIndexOf, substring, and concat.
- The concat method performs string concatenation similar to the + operator.
- The valueOf method has overloaded versions that take any primitive data type and return its string representation.
- The split method is used to break a string into tokens, utilizing a specified delimiter.
StringBuilder Class
- StringBuilder can store 16 characters by default if no argument is passed to its constructor.
- Common methods between String and StringBuilder include length.
- The setCharAt method allows changing a specific character within a StringBuilder object.
- The deleteCharAt method is used to remove a specific character in a StringBuilder object.
Tokenization
- Delimiters are characters that separate tokens in a string.
Wrapper Classes
- MIN_VALUE and MAX_VALUE are static final variables found in numeric wrapper classes, representing the limits for specific data types.
True/False Concepts
- Character testing methods like isLetter do not accept strings; they operate on individual characters.
- ToUpperCase returns characters unchanged if they are already uppercase.
- ToLowerCase does not inadvertently convert lowercase characters to uppercase.
- The startsWith and endsWith methods are case-sensitive and have both case-sensitive and case-insensitive versions.
- indexOf and lastIndexOf can find both characters and substrings.
- The String class's replace method can only replace individual characters but not substrings.
- In contrast, the StringBuilder class's replace method can replace both individual characters and substrings.
- Strings cannot be assigned to a StringBuilder object using the = operator.
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Description
Test your knowledge on Java Chapter 9, focusing on text processing and wrapper classes. This quiz includes various methods and their associated classes relevant to text manipulation in Java. Perfect for reinforcing key concepts in your programming studies.
