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Java Regex Basics and Pattern Matching

Here are 10 essential multiple-choice questions on Java Regex Basics and Pattern Matching, covering key concepts.

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Question 1

What does the Pattern class in Java represent?

It is a class that provides methods to match regular expressions
It is a class that stores strings for future matching
It is a class used to compile a regular expression into a pattern object
It is a class used to represent strings without any pattern matching

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Question 2

Which of the following is a method of the Matcher class used to check if a string matches the pattern?

find()
search()
matches()
isMatch()

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Question 3

Consider the following code snippet. What will be the output of this code?

Java

import java.util.regex.*;

public class Main {
    public static void main(String[] args) {
        String regex = "a*b";
        String input = "aaab";
        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(input);
        System.out.println(matcher.matches());
    }
}

true
false
aaab
Compile-time error

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Question 4

What does the find() method of the Matcher class do?

It checks if the entire string matches the pattern
It finds the next occurrence of the pattern in the input string
It replaces the matched string with another string
It splits the string based on the regular expression

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Question 5

Which of the following regular expression patterns represents a digit in Java?

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Question 6

What is the purpose of the Character class in the context of Java regex?

It is used to represent a character within a pattern
It is used to define the case sensitivity of regular expressions
It helps in escaping characters in a regular expression
It is used to create a regular expression pattern dynamically

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Question 7

How do you escape special characters in a Java regular expression?

By using the backslash (\)
By using double backslash (\\)
By using a Matcher object
By using parentheses ()

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Question 8

Which of the following will match a string that starts with a digit followed by any number of lowercase letters?

^\\d[A-Z]*$
^\\d[a-z]+$
^\\d[a-z]*$
\\d[a-z]*$

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Question 9

What is the purpose of the Pattern.compile() method in Java regex?

It matches a string with the provided pattern
It creates a new Matcher object from a regular expression pattern
It converts a regular expression into a human-readable format
It compiles a string into a regular expression pattern object

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Question 10

Consider the following regular expression pattern \\w+. What will it match?

One or more word characters (letters, digits, and underscores)
One or more non-word characters
Any character except a word character
Zero or more word characters

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Java Quiz

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