Practice 70 Java Regular Expression Programming Questions

Practice 70 Java Regular Expression Programming Questions

Q1.Write a Java program to check if a string contains only digits using a regular expression.  
Input:"123456"  
Expected Output:Valid

Q2.Write a Java program to check if a string contains only alphabets using a regular expression.  
Input:"HelloWorld"  
Expected Output:Valid

Q3.Write a Java program to validate an email address using a regular expression.  
Input:"test@example.com"  
Expected Output:Valid Email

Q4.Write a Java program to check if a string contains only lowercase letters using a regular expression.  
Input:"hello"  
Expected Output:Valid

Q5.Write a Java program to check if a string contains only uppercase letters using a regular expression.  
Input:"HELLO"  
Expected Output:Valid

Q6.Write a Java program to validate a phone number (10 digits) using a regular expression.  
Input:"9876543210"  
Expected Output:Valid Phone Number

Q7.Write a Java program to check if a string starts with a capital letter using a regular expression.  
Input:"Java"  
Expected Output:Valid

Q8.Write a Java program to validate a date format (YYYY-MM-DD) using a regular expression.  
Input:"2024-02-04"  
Expected Output:Valid Date

Q9.Write a Java program to validate a time format (HH:MM) using a regular expression.  
Input:"23:59"  
Expected Output:Valid Time

Q10.Write a Java program to check if a string contains only alphanumeric characters using a regular expression.  
Input:"Hello123"  
Expected Output:Valid

Q11.Write a Java program to check if a string contains special characters using a regular expression.  
Input:"Hello@123"  
Expected Output:Contains Special Characters

Q12.Write a Java program to validate a URL using a regular expression.  
Input:"https://www.google.com"  
Expected Output:Valid URL

Q13.Write a Java program to check if a string is a valid hexadecimal number using a regular expression.  
Input:"1A3F"  
Expected Output:Valid Hexadecimal

Q14.Write a Java program to check if a string contains spaces using a regular expression.  
Input:"Hello World"  
Expected Output:Contains Spaces

Q15.Write a Java program to extract all numbers from a given string using a regular expression.  
Input:"Order123456"  
Expected Output:123456

Q16.Write a Java program to check if a string follows a valid IPv4 address format using a regular expression.  
Input:"192.168.1.1"  
Expected Output:Valid IP Address

Q17.Write a Java program to validate a strong password using a regular expression (At least 8 characters, including a number, uppercase letter, and special character).  
Input:"Pass@1234"  
Expected Output:Valid Password

Q18.Write a Java program to check if a string starts with a digit using a regular expression.  
Input:"9Hello"  
Expected Output:Valid

Q19.Write a Java program to check if a string contains a valid domain name using a regular expression.  
Input:"example.com"  
Expected Output:Valid Domain

Q20.Write a Java program to replace multiple spaces with a single space using a regular expression.  
Input:"Hello   World"  
Expected Output:"Hello World"

Q21.Write a Java program to validate a vehicle registration number using a regular expression.  
Input:"MH-12-AB-1234"  
Expected Output:Valid Registration Number

Q22.Write a Java program to check if a string contains only whitespace using a regular expression.  
Input:"    "  
Expected Output:Only Whitespace

Q23.Write a Java program to check if a string is a palindrome (ignoring case and spaces) using a regular expression.  
Input:"madam"  
Expected Output:Palindrome

Q24.Write a Java program to validate a credit card number (16 digits) using a regular expression.  
Input:"1234567812345678"  
Expected Output:Valid Card Number

Q25.Write a Java program to extract all words from a given string using a regular expression.  
Input:"Hello, World!"  
Expected Output:["Hello", "World"]

Q26.Write a Java program to validate an Indian Aadhaar number using a regular expression.  
Input:"1234-5678-9123"  
Expected Output:Valid Aadhaar Number

Q27.Write a Java program to validate a ZIP code (5 or 6 digits) using a regular expression.  
Input:"560001"  
Expected Output:Valid ZIP Code

Q28.Write a Java program to extract all email addresses from a given string using a regular expression.  
Input:"My email is test@example.com"  
Expected Output:test@example.com

Q29.Write a Java program to validate a file name with a specific extension (e.g., .jpg, .png) using a regular expression.  
Input:"image.jpg"  
Expected Output:Valid File Name

Q30.Write a Java program to check if a string contains consecutive duplicate words using a regular expression.  
Input:"Hello Hello World"  
Expected Output:Contains Duplicate Words

Q31.Write a Java program to check if a string matches a specific pattern (e.g., "AB1234") using a regular expression.  
Input:"AB1234"  
Expected Output:Valid Format

Q32.Write a Java program to extract the first word from a sentence using a regular expression.  
Input:"Java is awesome"  
Expected Output:"Java"

Q33.Write a Java program to remove all special characters from a given string using a regular expression.  
Input:"Hello@World!"  
Expected Output:"HelloWorld"

Q34.Write a Java program to find all words that start with a specific letter using a regular expression.  
Input:"apple banana apricot orange" (Find words starting with 'a')  
Expected Output:["apple", "apricot"]

Q35.Write a Java program to extract the domain name from an email address using a regular expression.  
Input:"user@example.com"  
Expected Output:"example.com"

Q36.Write a Java program to validate a username (only letters, numbers, and underscore, 5-15 characters) using a regular expression.  
Input:"user_123"  
Expected Output:Valid Username

Q37.Write a Java program to count the number of words in a string using a regular expression.  
Input:"Hello World from Java"  
Expected Output:4 words

Q38.Write a Java program to check if a string follows the format "XX-YYYY" (where X is a letter and Y is a digit) using a regular expression.  
Input:"AB-2023"  
Expected Output:Valid Format

Q39.Write a Java program to validate a MAC address using a regular expression.  
Input:"00:1A:2B:3C:4D:5E"  
Expected Output:Valid MAC Address

Q40.Write a Java program to extract the area code from a phone number using a regular expression.  
Input:"(123) 456-7890"  
Expected Output:"123"

Q41.Write a Java program to check if a string contains repeated letters using a regular expression.  
Input:"Hello"  
Expected Output:Contains Repeated Letters

Q42.Write a Java program to validate a hexadecimal color code using a regular expression.  
Input:"#FF5733"  
Expected Output:Valid Color Code

Q43.Write a Java program to validate a LinkedIn profile URL using a regular expression.  
Input:"https://www.linkedin.com/in/johndoe"  
Expected Output:Valid LinkedIn URL

Q44.Write a Java program to extract hashtags from a tweet using a regular expression.  
Input:"I love #Java and #Programming"  
Expected Output:["#Java", "#Programming"]

Q45.Write a Java program to check if a string follows a valid credit card format (4-digit groups separated by dashes) using a regular expression.  
Input:"1234-5678-9101-1121"  
Expected Output:Valid Card Format

Q46.Write a Java program to extract all numbers from a mixed string using a regular expression.  
Input:"My order ID is 45678 and amount is 999"  
Expected Output:["45678", "999"]

Q47.Write a Java program to validate an ISBN number (10 or 13 digits) using a regular expression.  
Input:"978-3-16-148410-0"  
Expected Output:Valid ISBN

Q48.Write a Java program to validate a birth certificate number using a regular expression.  
Input:"BC-2023-12345"  
Expected Output:Valid Certificate Number

Q49.Write a Java program to validate a Twitter handle using a regular expression.  
Input:"@JavaCoder"  
Expected Output:Valid Twitter Handle

Q50.Write a Java program to remove duplicate words from a sentence using a regular expression.  
Input:"This is is a test test sentence"  
Expected Output:"This is a test sentence"

Q51.Write a Java program to extract monetary values from a string using a regular expression.  
Input:"Total cost is $250 and discount is $20"  
Expected Output:["$250", "$20"]

Q52.Write a Java program to check if a string contains a valid vehicle number plate using a regular expression.  
Input:"MH 12 AB 1234"  
Expected Output:Valid Number Plate

Q53.Write a Java program to validate a stock market ticker symbol using a regular expression.  
Input:"AAPL"  
Expected Output:Valid Ticker Symbol

Q54.Write a Java program to check if a given string follows a time format (HH:MM:SS) using a regular expression.  
Input:"14:30:15"  
Expected Output:Valid Time Format

Q55.Write a Java program to validate a driving license number using a regular expression.  
Input:"DL-1234-56789"  
Expected Output:Valid License Number

Q56.Write a Java program to validate an Indian PAN card number using a regular expression.  
Input:"ABCDE1234F"  
Expected Output:Valid PAN Card

Q57.Write a Java program to extract all words that start with a vowel using a regular expression.  
Input:"apple banana orange umbrella"  
Expected Output:["apple", "orange", "umbrella"]

Q58.Write a Java program to validate an employee ID using a regular expression (Format: EMP-XXXX).  
Input:"EMP-1234"  
Expected Output:Valid Employee ID

Q59.Write a Java program to extract usernames from email addresses using a regular expression.  
Input:"john.doe@example.com"  
Expected Output:"john.doe"

Q60.Write a Java program to check if a string follows the format "XYZ-123" using a regular expression.  
Input:"ABC-456"  
Expected Output:Valid Format

Q61.Write a Java program to validate a LinkedIn profile URL using a regular expression.  
Input:"https://linkedin.com/in/user"  
Expected Output:Valid LinkedIn URL

Q62.Write a Java program to check if a string contains HTML tags using a regular expression.  
Input:"<html><body>Hello</body></html>"  
Expected Output:Contains HTML Tags

Q63.Write a Java program to check if a string contains a valid mathematical expression using a regular expression.  
Input:"3 + 5 * 2"  
Expected Output:Valid Expression

Q64.Write a Java program to extract postal codes from a given string using a regular expression.  
Input:"My PIN is 560001 and my friend's is 110001"  
Expected Output:["560001", "110001"]

Q65.Write a Java program to validate a hexadecimal number (0x followed by digits) using a regular expression.  
Input:"0xA12F"  
Expected Output:Valid Hex Number

Q66.Write a Java program to validate a time format with AM/PM using a regular expression.  
Input:"02:30 PM"  
Expected Output:Valid Time Format

Q67.Write a Java program to extract phone numbers from a given string using a regular expression.  
Input:"Call me at 9876543210 or 9123456789"  
Expected Output:["9876543210", "9123456789"]

Q68.Write a Java program to validate a coupon code format (e.g., "SAVE20") using a regular expression.  
Input:"DISCOUNT50"  
Expected Output:Valid Coupon Code

Q69.Write a Java program to check if a string follows a valid variable name format using a regular expression.  
Input:"myVariable123"  
Expected Output:Valid Variable Name

Q70.Write a Java program to validate a chatbot command format (e.g., "/start") using a regular expression.  
Input:"/help"  
Expected Output:Valid Command