Java's Hidden 'this$0' Variable: A Memory Leak Source

@programiz 🚀 Mini Java Project: Rock Paper Scissors Game As part of my continuous learning in Java development, I built a simple Rock Paper Scissors console game using Java. 🔹 Concepts used in this project: • Java Basics & Control Flow • Loops and Conditional Statements • Random class for computer choice • Scanner for user input • Switch expressions • Basic game logic implementation The program allows a user to play 3 rounds against the computer, and it tracks wins, losses, and draws before declaring the final result. Small projects like this help strengthen problem-solving skills and improve understanding of Java logic building #Java #Programming #Coding #SoftwareDevelopment #LearningJourney #JavaDeveloper

Java has quietly improved a lot since version 9 — but if you work in enterprise codebases, you'd hardly know it. The old patterns are still everywhere, written by people who had no reason to change them. I wrote up a couple of small but practical upgrades around Maps: cleaner initialization with Map.of() and Map.ofEntries(), and a null-safe empty check that replaces the verbose two-condition if statement most of us have written a hundred times. Small things, but the kind that add up over a codebase. https://lnkd.in/dDVCPMnU #Java #SoftwareDevelopment #Programming

Atomic Variables in Java: Thread Safety Without Locks🧵⚛️ Today let's look at a powerful alternative that often sits right in between : Atomic variables. Atomic variables help solve a common problem where we need atomicity but we don't want locks. 🧠 What are atomic variables? Atomic variables in Java are classes that support lock-free , thread-safe operations on a single variables. They are part of the java.util.concurrent.atomic package. These variables prevent race conditions without using explicit locks or the synchronized keyword. 🧩 Simple example: import java.util.concurrent.atomic.AtomicInteger; class Counter {   private AtomicInteger count = new AtomicInteger(0);   public void increment() {     count.incrementAndGet();   }   public int getCount() {     return count.get();   } } 👉Explanation -> incrementAndGet() is atomic -> No synchronized block -> No explicit locks -> Multiple threads can safely update count ⚙️How atomic variables work 💠Use low-level CPU instructions (CAS- Compare and Swap) 💠Retry automatically if another thread updates the value 💠Avoid blocking other threads ➡️Faster and more scalable under contention. 🤔When to use Atomic Variables ✅Counters, flags, sequence numbers ✅Simple state updates ✅High-throughput systems 🧐Comparison volatile -> visibility only Atomic -> visibility + atomicity(single variable) synchronized -> visibility + atomicity + mutual exclusion 🧩 Key takeaway ➡️Atomic variables give you thread safety without locks ➡️They’re lightweight, fast, and expressive ➡️But they don’t replace proper synchronization everywhere #Java #Concurrency #Multithreading #AtomicInteger #SoftwareEngineering #Backend #Programming #LearningInPublic

Java Brain Teaser: Are you declaring what you think you're declaring? Take a look at these two lines of code. They look almost identical, but they behave very differently: Scenario A: int[] ids, types; Scenario B: int ids[], types; 🔍 The Breakdown In Scenario A, you get exactly what you’d expect: two int arrays. ids ➡️ int[] types ➡️ int[] In Scenario B, things get weird. By moving the brackets to the variable name, you change the scope of the array declaration: ids ➡️ int[] (Array) types ➡️ int (Simple primitive!) 💡 Why does this happen? Brackets on the Type: Apply to every variable in that declaration line. Brackets on the Name: Apply only to that specific variable. >>The "Clean Code" Takeaway Always place brackets on the type (int[] ids). Avoid declaring multiple variables of different types (or dimensions) on a single line. #Java #Programming #CleanCode #SoftwareDevelopment #CodingTips

Java Brain Teaser: Are you declaring what you think you're declaring? Take a look at these two lines of code. They look almost identical, but they behave very differently: Scenario A: int[] ids, types; Scenario B: int ids[], types; 🔍 The Breakdown In Scenario A, you get exactly what you’d expect: two int arrays. ids ➡️ int[] types ➡️ int[] In Scenario B, things get weird. By moving the brackets to the variable name, you change the scope of the array declaration: ids ➡️ int[] (Array) types ➡️ int (Simple primitive!) 💡 Why does this happen? Brackets on the Type: Apply to every variable in that declaration line. Brackets on the Name: Apply only to that specific variable. >>The "Clean Code" Takeaway Always place brackets on the type (int[] ids). Avoid declaring multiple variables of different types (or dimensions) on a single line. #Java #Programming #CleanCode #SoftwareDevelopment #CodingTips

𝗘𝘃𝗲𝗿 𝗻𝗼𝘁𝗶𝗰𝗲𝗱 𝘁𝗵𝗶𝘀? In Java, switch-case with Strings sometimes feels faster than if-else. At first, both look pretty similar. But internally, they don’t work the same way. 𝗪𝗶𝘁𝗵 𝗶𝗳-𝗲𝗹𝘀𝗲, 𝗝𝗮𝘃𝗮 𝗰𝗵𝗲𝗰𝗸𝘀 𝗲𝗮𝗰𝗵 𝗰𝗼𝗻𝗱𝗶𝘁𝗶𝗼𝗻 𝗼𝗻𝗲 𝗯𝘆 𝗼𝗻𝗲: if (str.equals("A")) else if (str.equals("B")) else if (str.equals("C")) So it keeps going until it finds a match. --- Switch-case does something smarter. Java converts the String into a hash and uses that to jump closer to the right case. So instead of checking everything sequentially, it narrows things down faster. --- That said… If you only have 2–3 conditions, it really doesn’t matter. The difference shows up when the number of conditions grows. --- I actually realized this while looking at a long if-else chain in one of our services 😄 --- The bigger takeaway? It’s not about memorizing syntax. It’s about understanding how things work under the hood. --- Have you ever come across something like this in Java? #java #javadeveloper #backenddevelopment #softwareengineering #coding #springboot #programming #developers #systemdesign #tech

Is Java Pass-by-Value or Pass-by-Reference? 👉 Java is strictly Pass-by-Value. Let’s understand why. In Java, method arguments are always passed as copies. For Primitives When a primitive variable (like int, double, etc.) is passed to a method, a copy of its value is created. Inside the method, we modify that copied value, not the original variable. So even if the method changes the parameter, the original variable outside the method remains unchanged. For Objects Objects work slightly differently. When an object is passed to a method, a copy of the reference value is passed. That copied reference still points to the same object in memory. So when we modify the object’s fields inside the method, we are actually modifying the same object, which is why the changes are visible outside the method. Let’s look at a quick visual to understand this better 👇 #Java #JavaDeveloper #BackendDevelopment #Programming #CodingInterview #SoftwareEngineering #JavaBasics #LearnToCode #TechLearning

Hey Future Developers 👋 Are you confused between variable names and parameters in Java? 🤔 Let’s solve it using the this keyword! 💡 In Java, this refers to the current object. 👉 It is mainly used to: • Differentiate instance variables from local variables • Call current class constructor • Pass current object as a parameter 💻 Example: class Student { String name; Student(String name) { this.name = name; // 'this' refers to instance variable } } 📌 Real-world example: Imagine you and your friend both have the same name. To identify yourself, you say “this is me” 😄 👉 Same way, Java uses this to refer to the current object. 🚀 Master small concepts like this to write clean and professional code! #Java #Programming #Coding #JavaBasics #Developers #Learning"

Interfaces in Java can also extend other interfaces. This allows one interface to build on top of another and combine multiple behaviours. Things that became clear : • an interface can extend one or more interfaces • the new interface inherits all the method declarations from the parent interfaces • any class implementing the child interface must provide implementations for all inherited methods • this helps organize related behaviours into structured layers • it also supports building more complex systems while keeping interfaces modular A simple example helps illustrate this idea : interface ICalculator { void add(int a, int b); void sub(int a, int b); } interface IAdvancedCalculator extends ICalculator { void mul(int a, int b); void div(int a, int b); } class CalculatorImpl implements IAdvancedCalculator { public void add(int a, int b) { System.out.println(a + b); } public void sub(int a, int b) { System.out.println(a - b); } public void mul(int a, int b) { System.out.println(a * b); } public void div(int a, int b) { System.out.println(a / b); } } Through this structure, interfaces can be combined and expanded while still maintaining clear rules for the implementing classes. #java #oop #programming #learning #dsajourney

🚀 Level Up Your Java: Enums + Varargs ✔️Ever wanted to write code that feels like a natural language? Let’s talk about two "oldies but goldies" in Java: Enums and Varargs. ❓The Why ✔️ Enums: Stop using "Magic Strings" or random integers. Use Enums to define a fixed set of constants (like Days, Statuses, or Roles). ✔️Varargs: Short for "Variable Arguments." It lets a method accept zero or multiple arguments without manually creating an array every time. 💻 The Code ✔️Check out how clean this PermissionManager looks: public class JavaTips { // Define clear, type-safe roles enum Role { ADMIN, EDITOR, VIEWER, GUEST } // Use Varargs (...) to check multiple roles at once public static void checkAccess(String user, Role... allowedRoles) { System.out.println("Checking access for: " + user); for (Role role : allowedRoles) { // Logic here System.out.println("Checking against: " + role); } } public static void main(String[] args) { // Look how clean this call is! // No 'new Role[] { ... }' needed. checkAccess("Alice", Role.ADMIN, Role.EDITOR); // Works with one argument too checkAccess("Bob", Role.VIEWER); } } 💡 The Pro-Tip ✔️ When using Varargs, always make it the last parameter in your method signature. ✔️Java needs to know exactly when the "variable" part starts! 🔑 Key Takeaways: 🔹 Readability: Your method calls look like sentences. 🔹 Safety: Enums prevent typos that happen with Strings. 🔹Flexibility: Varargs handle 1, 10, or 0 inputs gracefully. ❓ What’s your favorite "clean code" trick in Java? Let’s chat in the comments! 👇 #Java #Programming #CleanCode #SoftwareEngineering #Backend