Java 8 Date & Time API Simplifies Development

I used to overuse Optional in Java. Then I learned when not to use it. Optional is great for: • Return types • Avoiding null checks • Making intent clear But using it everywhere can actually make code worse. ❌ Don’t do this: class User { Optional<String> email; } Why? • Makes serialization messy • Complicates getters/setters • Adds noise where it’s not needed ✅ Better approach: Optional<String> findEmailByUserId(Long userId); Rule of thumb I follow now: 👉 Use Optional at the boundaries, not inside your models. Java gives us powerful tools, but knowing where to use them matters more than just knowing how. Clean code is less about showing knowledge and more about reducing confusion. What’s one Java feature you stopped overusing after some experience? #Java #CleanCode #BackendDevelopment #SoftwareEngineering #LearningInPublic #OptionalInJava #Optimization

Java Jump Scares Series #5 The Null Illusion Consider the following code snippet: ```java if (obj instanceof String s) {   System.out.println(s.length()); } ``` What happens if `obj` is null? Surprisingly, it evaluates to false without throwing an error or any signal. However, in this case: ```java return switch (obj) {   case String s -> s.length();   case Integer i -> i * 2;   default -> -1; }; ``` a NullPointerException occurs. It's crucial to add explicit null checks. Remember, null is not an instance; it represents nothing. Sometimes, nothing is what disrupts your logic. Java didn’t break — it did exactly what you instructed it to. ☕👻 #JavaDeveloper #BackendEngineer #SoftwareEngineer #JavaProgramming #JVM #APIDesign #CodeQuality #ProgrammingPitfalls

Once someone asked me what happens if I generate a java object from type Object passing as a parameter the value null... There're two possibilities for creating an object from type null, using Optional.of(null) (which is going to thrown a NullPointerException) and Optional.ofNullable(null) (Which is going to create an empty Optional) It was an interesting question, so I thought it was a good idea to share with you.

Java is no longer the "verbose" language we used to joke about. With Java 25, the entry barrier has been smashed. Instance Main Methods: No more static. Just void main(). Flexible Constructors: You can now run logic before calling super(). Markdown in Javadoc: Finally, documentation that looks good without HTML hacks. Question for the comments: Are you team "Modern Java" or do you still prefer the classic boilerplate? 👇 #Java25 #SoftwareEngineering #CodingLife #BackendDevelopment #codexjava_ If you’re still writing Java like it’s 2011 (Java 7), you’re missing out on a 50% productivity boost.

https://lnkd.in/dWiMj_Bx Java developers have complained about boilerplate for decades. Java 25’s compact source files aim to change that — making simple programs truly simple. A N M "Bazlur" Rahman explains what’s new. Curious if this improves your workflow? Read his article! #Java #Java25 #PatternMatching

Java☕ — JVM memory explained many bugs 🧠 Earlier, when my program crashed, I blamed logic. Then I saw errors like: 🔹OutOfMemoryError 🔹StackOverflowError That’s when I learned how JVM manages memory. 📝Stack Memory.. ✅Method calls ✅Local variables ✅Thread-specific 📝Heap Memory.. ✅Objects ✅Shared across threads #Java_Code int x = 10; // stack User u = new User(); // heap 📝Garbage Collector taught me this: Memory management is automatic — but not free. 📝Understanding JVM memory helped me: ✅Debug crashes faster ✅Write memory-friendly code ✅Respect object creation Java isn’t slow. Misusing memory is... #Java #JVM #MemoryManagement #GarbageCollection

You already know interfaces in Java. A Functional Interface is simply an interface with exactly one abstract method — nothing more. This constraint is intentional and it allows Java to represent behavior as a value. Runnable is a classic example. It defines a single contract: void run(); Because there is only one abstract method, the compiler can infer intent and accept a lambda as its implementation. Runnable task = () -> {   System.out.println("Executing task for Anwer Sayeed"); }; The lambda doesn’t replace Runnable. It implements its contract, concisely. This design choice is what enabled Java’s functional style without breaking its object-oriented foundations. #Java #FunctionalInterface #Runnable #LambdaExpressions #JavaDeveloper #CleanCode #Multithreading

📌 start() vs run() in Java Threads Understanding the difference between start() and run() is essential when working with threads in Java. 1️⃣ run() Method • Contains the task logic • Calling run() directly does NOT create a new thread • Executes like a normal method on the current thread Example: Thread t = new Thread(task); t.run();  // no new thread created 2️⃣ start() Method • Creates a new thread • Invokes run() internally • Execution happens asynchronously Example: Thread t = new Thread(task); t.start(); // new thread created 3️⃣ Execution Difference Calling run(): • Same call stack • Sequential execution • No concurrency Calling start(): • New call stack • Concurrent execution • JVM manages scheduling 4️⃣ Common Mistake Calling run() instead of start() results in single-threaded execution, even though Thread is used. 🧠 Key Takeaway • run() defines the task • start() starts a new thread Always use start() to achieve true multithreading. #Java #Multithreading #Concurrency #CoreJava #BackendDevelopment

The `main` method is the entry point of every Java application.** The JVM starts execution from: public static void main(String[] args) * `public` → accessible from anywhere * `static` → no object required to call it * `void` → does not return anything * `String[] args` → receives command-line arguments But with modern Java versions (including Java 21+ and continued in Java 25), we now have simpler ways to run programs, especially for small programs and learning purposes. You can write cleaner code using: * Simplified entry points * Implicit classes (in newer preview features) * Single-file execution However, the traditional `main` method is still the standard for production applications. — Understand the entry point. Master Java fundamentals. #Java25 #MainMethod #CoreJava JavaBasics Programming JavaDeveloper

Java#00 The lifecycle of an object in Java shows how it "is born," "lives," and "dies" in memory. First, it is created with `new` and occupies space on the Heap. Then, it is used as long as it has valid references. When there are no more references, it becomes inaccessible, and the Garbage Collector kicks in, freeing up the memory it occupied.