Java String Quiz: Practice with Medium Level Questions

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Questions and Answers

Which class is used to create and manipulate strings in Java?

Char

Sequence

String (correct)

Array

What is the term used to describe a sequence of characters written inside double-quotes in Java?

Char array

String pool

Sequence of characters

String literal (correct)

Which of the following statements is true about strings in Java?

Strings in Java can be modified directly

Strings in Java are immutable (correct)

Strings in Java are mutable

Strings in Java are stored in a char array

Where are strings stored in Java?

String pool Signup and view all the answers

What happens when a string operation is performed in Java?

A new string is created and returned Signup and view all the answers

How many methods are there to create strings in Java?

2 Signup and view all the answers

Which method is used to find the length of a string in Java?

length Signup and view all the answers

Which method is used to compare two strings and return 0 if they are equal?

compareTo Signup and view all the answers

Which method is used to concatenate two strings in Java?

concat Signup and view all the answers

Which method is used to convert a string to upper case in Java?

toUpperCase Signup and view all the answers

Which method is used to find the character at a specific index in a string?

charAt Signup and view all the answers

Which method is used to create a formatted string in Java?

format Signup and view all the answers

Which method is used to get a substring from a given string starting from a specified index till the end of the string?

substring(int beginIndex) Signup and view all the answers

Which method is used to check if a string contains a particular substring?

contains(String) Signup and view all the answers

Which method is used to replace all occurrences of a string in another string?

replace(String1, String2) Signup and view all the answers

Which method is used to replace only the first occurrence of a string in another string?

replaceFirst(String1, String2) Signup and view all the answers

Which method is used to find the index of a character or a string from a given string?

indexOf(String) Signup and view all the answers

Which method is used to remove extra spaces from the beginning and end of a string?

trim() Signup and view all the answers

Which method is used to find the last occurrence of a character or a string in a given string?

lastIndexOf() Signup and view all the answers

What is the output of the following code? String str = "Java Programming"; System.out.println(str.lastIndexOf("a"));

10 Signup and view all the answers

What is the output of the following code? String str = "Java Programming"; System.out.println(str.lastIndexOf('a', 5));

3 Signup and view all the answers

Which method is used to check whether a string is empty or not?

isEmpty() Signup and view all the answers

What is the output of the following code? String str = "Java Programming"; String s = ""; System.out.println(str.isEmpty()); System.out.println(s.isEmpty());

false, true Signup and view all the answers

Which method is used to split a string based on a delimiter/regular expression?

split() Signup and view all the answers

Which of the following is true about strings in Java?

Strings are immutable in Java Signup and view all the answers

What is the purpose of string methods in Java?

To modify existing strings Signup and view all the answers

Why is it important to learn and understand string methods in Java?

They are essential for working with text and manipulating strings Signup and view all the answers

What can practice and familiarity with string methods help you achieve?

Efficient and effective string manipulation Signup and view all the answers

Which of the following is NOT true about strings in Java?

Strings can be modified directly Signup and view all the answers

What is the purpose of string methods in Java programming?

To manipulate and modify strings Signup and view all the answers

Study Notes

Java Strings

The String class is used to create and manipulate strings in Java.

String Definition

A sequence of characters written inside double-quotes is referred to as a string literal.

String Characteristics

Strings in Java are immutable, meaning they cannot be changed once created.
Strings are stored in the string pool in Java.

String Operations

When a string operation is performed in Java, a new string is created, and the original string remains unchanged.

Creating Strings

There are two methods to create strings in Java: using the String keyword and using the new keyword.

String Methods

The length() method is used to find the length of a string in Java.
The equals() method is used to compare two strings and return 0 if they are equal.
The concat() method is used to concatenate two strings in Java.
The toUpperCase() method is used to convert a string to upper case in Java.
The charAt() method is used to find the character at a specific index in a string.
The String.format() method is used to create a formatted string in Java.
The substring() method is used to get a substring from a given string starting from a specified index till the end of the string.
The contains() method is used to check if a string contains a particular substring.
The replaceAll() method is used to replace all occurrences of a string in another string.
The replaceFirst() method is used to replace only the first occurrence of a string in another string.
The indexOf() method is used to find the index of a character or a string from a given string.
The trim() method is used to remove extra spaces from the beginning and end of a string.
The lastIndexOf() method is used to find the last occurrence of a character or a string in a given string.
The isEmpty() method is used to check whether a string is empty or not.
The split() method is used to split a string based on a delimiter/regular expression.

String Methods Examples

The output of the code String str = "Java Programming"; System.out.println(str.lastIndexOf("a")); is 15.
The output of the code String str = "Java Programming"; System.out.println(str.lastIndexOf('a', 5)); is 4.

Importance of String Methods

The purpose of string methods in Java is to perform various operations on strings, such as manipulation, comparison, and searching.
It is important to learn and understand string methods in Java because they are widely used in programming and can help you achieve efficient and effective coding.
Practice and familiarity with string methods can help you achieve better programming skills and solve complex problems.

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Description

String Formatting and Substrings Quiz: Test your knowledge on string formatting and substring methods in Java. Learn how to format float numbers with specified decimal points and retrieve substrings from a string.

Java String (Medium)

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