Java Programming Interview Questions — Part I 🚀

A curated collection of 55 Java programs every Tester, SDET, and Automation Engineer should practice before their next technical interview.

🔥 Why This Repo

• Covers interview-relevant Java programs.

• Designed for QA & Automation professionals.

• Each file includes a simple, clean solution.

• Builds logic — not just syntax memorization.

  Complete Java Program List

Write a Java program to find ASCII value of a character

Write a Java program to add two Integer

Write a Java program to check whether a given character is an alphabet or not

Write a Java program for Alphabet or Vowel in a String

Write a Java program for Anagram Number

Write a Java program for Anagram String

Write a Java program for Armstrong Number

Write a Java program for Array Equality Check

Write a Java program to convert Integer to String

Write a Java program to Count the Number of Occurrence of the Character in the Given String

Write a Java program to Count the number of words in a given string

Write a Java program for Divisible by 5

Write a Java program for duplicate count of Number of Array

Write a Java program for Even and odd Numbers from Array

Write a Java program to find Even or odd Number

Write a Java program to find factorial of a Number using Recursion

Write a Java program to find Maximum and Minimum in Array

Write a Java program to find the position of a word in a given String

Write a Java program to find the sum of the first 100 natural numbers

Write a Java program for Fibonacci Series

Write a Java program for leap year

Write a Java program for Linear Array

Write a Java program for Missing Number in Array

Write a Java program for Palindrome Number

Write a Java program to Palindrome String

Write a Java program to check Prime Number

Write a Java program for Prime Number from 1 to 100

Write a Java program to print all vowels in a given string

Write a Java program to print the duplicate character in a given string and total count of duplicate occurrences

Write a Java program that multiplies two floating point numbers

Write a Java program that uses a loop (for) to print values of i from 1 to 5

Write a Java program that calculates the length of a string using different methods

Write a Java program that prints a star pattern in the shape of a triangle followed by an inverted triangle

Write a Java program to calculate and print the quotient and remainder

Write a Java program to calculate the factorial of a given number using recursion

Write a Java program to check whether a given number is positive, zero, or negative

Write a Java program to demonstrate about generating random numbers and strings

Write a Java program for Removing duplicates from an array

Write a Java program for Reverse an Array

Write a Java program to Reverse a Number

Write a Java program to Reverse a String

Write a Java program for Smallest a Array

Write a Java program for Sorting Arrays in Names

Write a Java program for Sum of Elements in Array

Write a Java program for Sum of largest three Number

Write a Java program for Sum of two digits of number

Write a Java program to Swap two Integer with third variable

Write a Java program to Swap two Integers without a third variable

Write a Java program to Swap two String without a third variable

Write a Java program to write without Main Method

Write a Java program to remove all characters from a string except lowercase alphabets

Write a Java program to remove all special characters from a given string and print only the alphanumeric characters

Write a Java program to remove all white spaces from a given string

Write a Java program to read an integer input from the user and print the entered number

Write a Java program to print your name 1000 times without using any loop

📂 Topics Covered

• Core Java (loops, conditionals, recursion)
• Strings (reverse, palindrome, frequency count)
• Arrays (sorting, duplicates, missing numbers)
• Mathematical logic (prime, Fibonacci, factorial)
• Pattern printing, random numbers, input handling

🧠 Perfect For

• Manual Testers moving into Automation
• SDETs improving Java skills
• Freshers preparing for QA interviews

🚀 How to Use

1. Clone repo:
   git clone https://github.com/ArpitChoubey/JavaProgrammingInterviewQuestion-Part-I.git
2. Open in Eclipse or IntelliJ
3. Run each .java file and learn by doing
4. ⭐ Star the repo if you find it useful

🤝 Contribute

Pull Requests (PRs) are welcome for:

• New Java problems
• Code optimization
• Documentation improvements

👨‍💻 Author

Arpit Choubey
SDET | QA | Automation Engineer
🔗 LinkedIn | Medium

⭐ Support

If this repository helps you, please Star 🌟 it.
Your support motivates me to release Part II soon!