Simplify Unix-style File Path with Java Stack Solution

I remember staring at Java code wondering... Why is this variable private? Why can't I extend this class? Why does this method work without an object? Modifiers confused me for a long time. So I built the guide I wish I had back then. A complete, colorful visual guide to Java Modifiers — covering everything in one document: ACCESS MODIFIERS 🔴 private — your own class only 🟢 default — same package family 🟠 protected — package + inherited subclasses 🔵 public — accessible from everywhere NON-ACCESS MODIFIERS 🟣 static — belongs to the class, not the object 🟡 final — cannot be changed, overridden, or extended 🔵 abstract — must be completed by subclass 🔴 synchronized — one thread at a time 🌿 volatile & transient — memory + serialization control Each modifier comes with: → Clear rules (no fluff) → Real-world analogies that actually make sense → VSCode-style dark code examples → Color-coded visibility tables Whether you're a beginner trying to understand encapsulation or prepping for a Java interview — this one is for you. PDF attached — free to download and share! Save this post for your next Java revision session. #Java #JavaProgramming #OOP #AccessModifiers #LearnJava #Programming #Developer #CodeNewbie #SoftwareEngineering #TechLearning

Just shipped my first open-source Java library : llm4j-schema If you're integrating LLMs (ChatGPT, Claude) into Java or Spring Boot apps,  you know the pain: the model returns raw text, you parse it manually,  hope the JSON is valid, add retry logic... llm4j-schema solves this. Define a Java Record, get a typed object back: @LLMSchema public record ProductReview(   String productName,   int rating,   String summary ) {} ProductReview review = extractor.extract(ProductReview.class, userText); - Type-safe Java objects from any LLM - Spring Boot starter, 2 min setup   - Auto-retry on parse failure - OpenAI + Anthropic support - Available on Maven Central The Java ecosystem is way behind Python when it comes to AI tooling.  This is my contribution to close that gap. GitHub: https://lnkd.in/e37jtdut If you find it useful, a Star on the repo goes a long way, it helps other Java developers discover the project! Would love to hear from Java devs, what's your biggest pain point  when integrating LLMs in your stack? #Java #OpenSource #AI #SpringBoot #LLM #Developer

Java 17 Feature: Record Classes What is a Record Class? A record class is mainly used to create DTOs (Data Transfer Objects) in a simple and clean way. Why DTOs? DTOs are used to transfer data: • Between services • From backend to frontend Key Features of Record Classes: Immutable by default (data cannot be changed after creation) Less code (no need to write getters, constructors, etc.) When you create a record, Java automatically provides: Private final fields All-arguments constructor Getter methods (accessor methods) toString(), equals(), hashCode() Example: public record Customer(int customerId, String customerName, long phone) {} Usage: Customer customer = new Customer(1011, "John", 9890080012L); System.out.println(customer.customerId()); Important Points: Record class is implicitly final Cannot extend other classes Internally extends java.lang.Record Can implement interfaces (normal or sealed) Can have static methods and instance methods Cannot have extra instance variables With Sealed Interface: public sealed interface UserActivity permits CreateUser, DeleteUser { boolean confirm(); } public record CreateUser() implements UserActivity { public boolean confirm() { return true; } } Before Java 17: We used Lombok to reduce boilerplate code. After Java 17: Record classes make code: Cleaner Shorter Easier to maintain #Java #Java17 #BackendDevelopment #FullStackDeveloper #Programming #SoftwareEngineering

I just wanted to share something that really changed my life recently while I was coding in Java. As someone who has been working with this language for a long time, I always hated how we had to handle long Strings, like SQL queries or JSONs. It was a mess of \n and + everywhere, right? But then I started using Java Text Blocks (which came out in Java 15), and wow... it’s so much better! Here is why I think they are awesome: No more + signs: You just use three double quotes """ and write your text normally. It looks exactly like the final result. Easy to read: Since you don't have all those concatenation symbols, your code stays clean. My eyes are very happy now! Smart spaces: Java is smart enough to manage the indentation, so your code stays aligned but the String doesn't get a bunch of unnecessary spaces at the beginning. Check out this quick example of how I'm writing my SQL now: If you are still using the old way, please do yourself a favor and try Text Blocks. It makes the developer's life much easier and the code way more clean. #Java #Backend #CodingTips #CleanCode #SoftwareEngineering

Most Java devs know Collections exist. Few know which one to actually pick. 🧵 After years of backend work, I still see the same mistakes in code reviews: LinkedList used where ArrayList is 3x faster HashMap in multi-threaded code with no sync Custom objects in HashSet without equals() + hashCode() So I built this visual cheat sheet. 9 slides. Every collection. Real trade-offs. Here's what's inside 👇 📌 Full hierarchy from Iterable down to every implementation 📌 ArrayList vs LinkedList =>when each actually wins 📌 HashSet / LinkedHashSet / TreeSet => ordering guarantees explained 📌 HashMap vs TreeMap vs LinkedHashMap =>feature table 📌 Queue & Deque => why ArrayDeque beats Stack and LinkedList 📌 Big-O cheat sheet => all 10 collections in one table 📌 Top 5 interview questions => with answers that impress 🚀 My Daily Java Collections Decision Rule Confused which collection to use? This quick guide helps me every day 👇 👉 Need fast random access? → ArrayList ⚡ 👉 Need unique elements + fast lookup? → HashSet 🔍 👉 Need key-value pairs (default choice)? → HashMap 🗂️ 👉 Need sorted data? → TreeMap / TreeSet 🌳 👉 Need Stack / Queue operations? → ArrayDeque 🔄 👉 Need priority-based processing? → PriorityQueue 🏆 ♻️ Repost if this helps a Java dev on your feed. #Java #JavaDeveloper #Collections #DataStructures #Backend #BackToBasics #SpringBoot #CodingInterview #SoftwareEngineering #Programming

🚀 Day 18 – Java Streams: Writing Cleaner & Smarter Code Today I started exploring Java 8 Streams—a powerful way to process collections. Instead of writing traditional loops: List<Integer> nums = Arrays.asList(1, 2, 3, 4, 5); for (int n : nums) { if (n % 2 == 0) { System.out.println(n); } } 👉 With Streams: nums.stream() .filter(n -> n % 2 == 0) .forEach(System.out::println); --- 💡 What I liked about Streams: ✔ More readable and expressive ✔ Encourages functional style programming ✔ Easy to chain operations (filter, map, reduce) --- ⚠️ Important insight: Streams don’t store data—they process data pipelines 👉 Also: Streams are lazy → operations execute only when a terminal operation (like "forEach") is called --- 💡 Real takeaway: Streams are not just about shorter code—they help write clean, maintainable logic when working with collections. #Java #BackendDevelopment #Java8 #Streams #LearningInPublic

Ever wondered why changing one variable sometimes changes everything in Java? Today I finally understood a concept that used to confuse me a lot — Pass by Value vs Pass by Reference (memory perspective). At first, it felt tricky… but once I visualized how memory works, everything started making sense. What I learned: [1] Pass by Value (Definition): A copy of the actual value is passed to another variable. 👉 Both variables work independently. Example: int x = 10; int y = x; // copy y = 20; System.out.println(x); // 10 System.out.println(y); // 20 ➡️ Changing y does NOT affect x [2] Pass by Reference (Concept in Java objects): Actually, Java is always pass by value… BUT for objects, the value being passed is the reference (address). 👉 So multiple variables can point to the same object in memory. Example: Car a = new Car(); a.name = "Maruti"; Car b = a; // reference copy b.name = "Kia"; System.out.println(a.name); // Kia ➡️ Changing b also changes a because both point to the same object. 💡 Real-life analogy: It’s like one person having multiple names — Parents call you one name, friends call you another… but it’s still YOU. Same in Java: Different references ➝ Same object ➝ Same changes. 🔑 Key Takeaways: Java is always pass by value For objects, the value = reference (address) Multiple references can point to the same object Changing via one reference affects all This concept really changed how I look at Java objects and memory. Still learning, still improving… one concept at a time #Java #Programming #LearningJourney #Coding #JavaDeveloper #BeginnerDeveloper #SoftwareDevelopment #100DaysOfCode

Day 7 of #100DaysOfCode — Java is getting interesting ☕ Today I explored the Java Collections Framework. Before this, I was using arrays for everything. But arrays have one limitation — fixed size. 👉 What if we need to add more data later? That’s where Collections come in. 🔹 Key Learnings: ArrayList grows dynamically — no size worries Easy operations: add(), remove(), get(), size() More flexible than arrays 🔹 Iterator (Game changer) A clean way to loop through collections: hasNext() → checks next element next() → returns next element remove() → safely removes element 🔹 Concept that clicked today: Iterable → Collection → List → ArrayList This small hierarchy made everything much clearer. ⚡ Array vs ArrayList Array → fixed size ArrayList → dynamic size Array → stores primitives ArrayList → stores objects Still exploring: Set, Map, Queue next 🔥 Consistency is the only plan. Showing up every day 💪 If you’re also learning Java or working with Collections — let’s connect 🤝 #Java #Collections #ArrayList #100DaysOfCode #JavaDeveloper #LearningInPublic

🔥 Day 16: Method References (:: operator) in Java A powerful feature introduced in Java 8 that makes your code cleaner and more readable 👇 🔹 What is Method Reference? 👉 Definition: A shorter way to refer to a method using :: instead of writing a lambda expression. 🔹 Why Use It? ✔ Reduces boilerplate code ✔ Improves readability ✔ Works perfectly with Streams & Functional Interfaces 🔹 Lambda vs Method Reference 👉 Using Lambda: list.forEach(x -> System.out.println(x)); 👉 Using Method Reference: list.forEach(System.out::println); ✨ Cleaner & simpler! 🔹 Types of Method References 1️⃣ Static Method Reference ClassName::staticMethod 2️⃣ Instance Method (of object) object::instanceMethod 3️⃣ Instance Method (of class) ClassName::instanceMethod 4️⃣ Constructor Reference ClassName::new 🔹 Examples ✔ Static: Math::max ✔ Instance: System.out::println ✔ Constructor: ArrayList::new 🔹 When to Use? ✔ When lambda just calls an existing method ✔ To make code shorter and cleaner ✔ With Streams and Functional Interfaces 💡 Pro Tip: If your lambda looks like 👉 (x) -> method(x) You can replace it with 👉 Class::method 📌 Final Thought: "Method Reference = Cleaner Lambda" #Java #MethodReference #Java8 #Streams #Programming #JavaDeveloper #Coding #InterviewPrep #Day16

🚨 Can a Thread call start() twice in Java? Short answer — No. And we learned this the hard way in production. 😬 😓 The real story We had a payment retry system. When a payment failed, our code called thread.start() again on the same thread to retry. Seemed logical... until we saw IllegalThreadStateException crashing the entire service at midnight. 💀 🔍 Why does this happen? Once a thread finishes, it moves to a TERMINATED state. Java does not allow restarting a dead thread — ever. ❌ Wrong: t.start(); t.start(); → 💥 CRASH ✅ Right: Create a new Thread each time, or use ExecutorService 💡 How we fixed it Replaced raw threads with ExecutorService. Every retry = a new task submitted to the pool. No crashes. No headaches. 🧠 Remember: 🔁 Thread lifecycle → New → Runnable → Running → Terminated 🚫 Once terminated — cannot restart ✅ Always use a new Thread or ExecutorService One line of mistake. One midnight crash. One lesson for life. 🙂 Have you ever hit this bug? Drop a comment 👇 #Java #Multithreading #Threading #JavaDeveloper #BackendDevelopment #CodingTips #SoftwareEngineering