Java Code Output: Array Modification and Printing

🚀 Java Streams Interview Gem: Find Duplicate Numbers in a List Working with collections is common, but identifying duplicates efficiently is a must-have skill for any Java developer 💡 Here’s how you can find duplicate numbers using Java Streams 👇 🔹 Approach: We use a Set to track elements and filter duplicates while streaming the list. 🔹 Code: import java.util.*; import java.util.stream.*; public class FindDuplicates { public static void main(String[] args) { List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 2, 5, 6, 3, 7, 1); Set<Integer> seen = new HashSet<>(); Set<Integer> duplicates = numbers.stream() .filter(n -> !seen.add(n)) .collect(Collectors.toSet()); System.out.println("Duplicate Numbers: " + duplicates); } } 🔹 Output: Duplicate Numbers: [1, 2, 3] 🔹 How it works? ✔ seen.add(n) returns false if the element is already present ✔ We filter those elements → duplicates ✔ Collect them into a Set to avoid repeated duplicates 💥 Alternative (Using Grouping): 🔥 Mastering Streams = Cleaner + More Functional Code #Java #JavaStreams #CodingInterview #Developers #Programming #Tech #100DaysOfCode

💡 Java Interview Question How do you find the common elements from three lists in Java? Here’s a simple example: ✅ Two approaches: Using retainAll() with Set Using Java 8 Streams public class CommonElementFrom3List { public static void main(String[] args){ List<Integer> list1 = Arrays.asList(1, 2, 3, 4, 5); List<Integer> list2 = Arrays.asList(3, 4, 5, 6, 7); List<Integer> list3 = Arrays.asList(5, 6, 7, 8, 3); Set<Integer> common = new HashSet<>(list1); common.retainAll(list2); common.retainAll(list3); System.out.println(common); List<Integer> list = list1.stream() .filter(list2::contains) .filter(list3::contains) .distinct() .collect(Collectors.toList()); System.out.println(list); } } 📌 Output: [3, 5] ❓ Question for you: Which approach would you prefer in a real-world scenario and why? Also, how would you handle duplicate elements efficiently? #Java #CodingInterview #JavaDeveloper #Programming #TechLearning

💻 Java Developers — Can you spot the bug? 👀 I wrote this simple code to take user input: Scanner sc = new Scanner(System.in); System.out.println("Enter size:"); int size = sc.nextInt(); String[] foods = new String[size]; for(int i = 0; i < foods.length; i++) { System.out.println("Enter value at " + i); foods[i] = sc.nextLine(); } 👉 Expected behavior: It should ask me to enter values one by one. 👉 Actual behavior: Enter value at 0 Enter value at 1 ⚠️ It skips the first input! ❓ Question: Why is this happening? A) Loop issue B) Scanner bug C) Input buffer issue D) Something else 👇 Drop your answer in the comments (no Googling 😄) I’ll share the correct explanation in the comments later 👇 #Java #Programming #CodingChallenge #Developers #Learning

🚀 Java Streams Interview Question Given a list of integers, remove duplicates and return a sorted list using Stream API. import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; public class Main { public static void main(String[] args) { List<Integer> numbers = Arrays.asList(5, 3, 8, 1, 3, 5, 9, 2, 8); List<Integer> sortedUniqueNumbers = numbers.stream() .distinct() .sorted() .collect(Collectors.toList()); System.out.println(sortedUniqueNumbers); } } Output: [1, 2, 3, 5, 8, 9] 🔹 distinct() removes duplicate elements 🔹 sorted() arranges the elements in ascending order 🔹 collect(Collectors.toList()) converts the stream back to a list #Java #JavaStreams #CodingInterview #Programming #Developers #SoftwareEngineering #BackendDevelopment

Day 9 Java Practice: Find the First Non-Repeated Character in a String While practicing Java, I worked on a classic string problem: 👉 Find the first non-repeated character in a given string. For example, in the string "swiss", the first character that does not repeat is 'w'. To solve this, I used a LinkedHashMap to store character counts while preserving insertion order. Then I iterated through the map to find the first character with count = 1. ================================================== // Online Java Compiler // Use this editor to write, compile and run your Java code online import java.util.*; class Main {   public static void main(String[] args) {           String s="swiss";           char[] words=s.toCharArray();           Map<Character,Integer>map=new LinkedHashMap<Character,Integer>();           for(char word:words)     {      map.put(word,map.getOrDefault(word,0)+1);     }           for(Map.Entry<Character,Integer>entry:map.entrySet())     {       if(entry.getValue()==1)       {         System.out.println("First non-repeated character in the string is:"+entry.getKey());         break;       }     }               } } Output:First non-repeated character in the string is:w This was a good exercise to understand: Character frequency counting Importance of insertion order using LinkedHashMap String traversal logic #AutomationTestEngineer #Selenium #Java #CodingPractice #ProblemSolving

🚀 Java Interview Series – Day 25 What is the finally block in Java? The finally block is used to execute important code regardless of whether an exception occurs or not. It is always executed after the try and catch blocks (except in rare cases like JVM shutdown). 🔹 Where it fits: • try → code that may throw exception • catch → handles exception • finally → always executes Why is this important? ✔ Ensures resource cleanup ✔ Prevents resource leaks ✔ Guarantees execution of critical code 💡 Example: When working with: Database connections File streams Network sockets Even if an exception occurs, the finally block ensures resources are properly closed. ⚡ Key Insight: In modern Java, try-with-resources is often preferred as it automatically handles resource closing—but finally is still important to understand. 💬 Interview Tip: Always mention: “Executes always” Resource cleanup use cases Difference from try-with-resources Handling failures properly is what separates beginner code from production-ready systems. #Java #JavaDeveloper #ExceptionHandling #FinallyBlock #CleanCode #BackendDevelopment #SoftwareEngineering #TechInterview #CodingInterview #SystemDesign #Developers #LearningInPublic #CareerGrowth #IndiaJobs #USJobs #UKJobs #AustraliaJobs

🚀 Java Basic That Many Ignore: What is String[] args in main()? 🤔 We write this every day: public static void main(String[] args) { System.out.println("Hello"); } 👉 But what exactly is args? 💡 args = Command Line Arguments It is an array of Strings passed when running your program 👉 Example: public class Test { public static void main(String[] args) { System.out.println(args[0]); } } Run this: java Test Hello 👉 Output: Hello 🤯 Important Points: args is just a variable name (you can change it) It is always an array of String It can be empty (no arguments passed) 🔥 Fun Fact: public static void main(String[] xyz) 👉 This also works! 😄 ⚠️ Be careful: System.out.println(args[0]); ❌ If no argument → ArrayIndexOutOfBoundsException 💡 Safe way: if (args.length > 0) { System.out.println(args[0]); } Small concept… but important for interviews & real-world usage 💪 #Java #Programming #Coding #JavaDeveloper #InterviewPrep #Developers

Most Java developers write code. Very few write good Java code🔥 Here are 10 Java tips every developer should know 👇 1. Prefer interfaces over implementation → Code to "List" not "ArrayList" 2. Use "StringBuilder" for string manipulation → Avoid creating unnecessary objects 3. Always override "equals()" and "hashCode()" together → Especially when using collections 4. Use "Optional" wisely → Avoid "NullPointerException", but don’t overuse it 5. Follow immutability where possible → Makes your code safer and thread-friendly 6. Use Streams, but don’t abuse them → Readability > fancy one-liners 7. Close resources properly → Use try-with-resources 8. Avoid hardcoding values → Use constants or config files 9. Understand JVM basics → Memory, Garbage Collection = performance impact 10. Write meaningful logs → Debugging becomes 10x easier Clean code isn't about writing more. It’s about writing smarter. Which one do you already follow? 👇 #Java #JavaDeveloper #SoftwareEngineering #BackendDevelopment #SpringBoot #CleanCode #Programming #Developers #TechTips #CodingLife

🔥 Preparing for Java Interviews? Here are some must-know questions with simple explanations 👇 OOPS (Object-Oriented Programming) Q1: What is OOPS? 👉 OOPS is a programming concept based on objects and classes. 💡 It includes: Encapsulation, Inheritance, Polymorphism, Abstraction Q2: What is Encapsulation? 👉 Wrapping data + methods into a single unit (class) 📝 Achieved using private variables + getters/setters Q3: What is Inheritance? 👉 One class acquires properties of another class 📝 extends keyword Q4: What is Polymorphism? 👉 Same method, different behavior 📝 Method Overloading & Overriding 🔹 Strings Q5: Difference between String and StringBuilder? 👉 String is immutable (cannot change) 👉 StringBuilder is mutable (can change) Q6: What is String Pool? 👉 Memory area where Java stores string literals 🔹 Arrays Q7: What is an Array? 👉 Collection of same data type elements stored in contiguous memory Q8: Difference between Array and ArrayList? 👉 Array → Fixed size 👉 ArrayList → Dynamic size 🔹 Collections Q9: What is Collection Framework? 👉 Set of classes/interfaces to store and manipulate data Q10: List vs Set? 👉 List → Allows duplicates 👉 Set → No duplicates Q11: HashMap vs HashSet? 👉 HashMap → Key-Value pairs 👉 HashSet → Only values (no duplicates) 🔹 Exceptions Q12: What is Exception? 👉 Runtime error that disrupts program flow Q13: Checked vs Unchecked Exception? 👉 Checked → Compile-time (IOException) 👉 Unchecked → Runtime (NullPointerException) Q14: What is try-catch? 👉 Used to handle exceptions 🔹 Threads Q15: What is Thread? 👉 Smallest unit of process for multitasking Q16: How to create a Thread? 👉 Extend Thread class OR Implement Runnable Q17: What is Multithreading? 👉 Running multiple threads simultaneously #Java #OOPS #InterviewPreparation #Freshers #SoftwareDeveloper #Coding #Collections #Multithreading #Exceptions

🚀 Java Puzzle: Why this prints "100" even after using "final"? 🤯 Looks like a bug… but it’s actually Java behavior 👇 👉 Example: final int[] arr = {1, 2, 3}; arr[0] = 100; System.out.println(arr[0]); // 100 😮 👉 Wait… "final" but still changing? 🤔 💡 Reality of "final": - "final" → reference cannot change - NOT → object data cannot change 👉 So: - ❌ "arr = new int[]{4,5,6}" → not allowed - ✅ "arr[0] = 100" → allowed --- 🔥 Now the REAL twist 😳 final StringBuilder sb = new StringBuilder("Java"); sb.append(" Developer"); System.out.println(sb); // Java Developer 😮 👉 Again changing despite "final" 🔥 Golden Rule: 👉 "final" means: - You cannot point to a new object - But you CAN modify the existing object 💡 Common misconception: 👉 Many think "final = constant" (NOT always true) 💬 Did you also think "final" makes everything immutable? #Java #JavaDeveloper #Programming #Coding #100DaysOfCode #TechTips #JavaTips #InterviewPrep #Developers #SoftwareEngineering