Last week, we faced a critical production issue that reminded me how tricky multithreading can be in Java. 🔍 Problem: Our application suddenly became slow under load. CPU usage was low, but requests were timing out. 🧠 Root Cause: After analyzing thread dumps using tools like jstack and VisualVM, we discovered a classic deadlock situation. Two threads were waiting on each other’s locks — and nothing was moving forward. ⚠️ Key Learnings: Always maintain a consistent lock ordering to avoid deadlocks Avoid excessive use of synchronized blocks Prefer high-level concurrency utilities like ExecutorService, ReentrantLock, and ConcurrentHashMap Monitor thread pools in production (size, queue, rejection policy) Use tools like jconsole, VisualVM, and thread dumps regularly 💡 Pro Tip: Multithreading issues rarely appear in development — they show up under real traffic. Always design with concurrency in mind. 👨💻 As developers, writing correct concurrent code is not just a skill — it's a responsibility. #Java #Multithreading #BackendDevelopment #ProductionIssues #SoftwareEngineering #Debugging #TechLearning

Race Condition : happens when multiple threads access and modify shared data at the same time, and the final result depends on the timing of execution. example: int count = 0; public void increment() { count++; } two threads execute count++ simultaneously: Both read count = 0 Both increment to 1 Both write back 1 Final result = 1 instead of 2 Problem: Data inconsistency Unpredictable results Solution: Use synchronization (synchronized) Use locks (ReentrantLock) Use atomic classes (AtomicInteger) Thread Starvation : thread is “waiting forever” while others keep running. example: Thread t1 = new Thread(task); t1.setPriority(Thread.MAX_PRIORITY); Thread t2 = new Thread(task); t2.setPriority(Thread.MIN_PRIORITY); t2 may rarely or never execute. problem: Some threads never complete Solution: ReentrantLock lock = new ReentrantLock(true); #Java #BackendDevelopment #SoftwareEngineering #MultiThreading #Concurrency #JavaPerformance #CodingTips #Programming #SystemDesign

Day 55/100 – LeetCode Challenge Problem: Triangle Today I solved the “Triangle” problem, which is a classic dynamic programming question focused on finding the minimum path sum from top to bottom. Instead of starting from the top and exploring all possible paths, I approached this problem from the bottom. I initialized a DP array with the values of the last row of the triangle. Then, I moved upward row by row, updating each element by adding the minimum of the two adjacent values from the row below. This bottom-up approach reduces the problem size at each step and avoids unnecessary recomputation. By the time I reached the top, the first element of the DP array represented the minimum path sum. This method is efficient because it reuses space and avoids building a full 2D DP table. The solution runs in O(n²) time with O(n) space complexity. This problem reinforced how changing the direction of thinking — bottom-up instead of top-down — can simplify dynamic programming problems significantly. Fifty-five days in. The focus is now on writing optimal solutions with better space efficiency. #100DaysOfLeetCode #Java #DSA #DynamicProgramming #ProblemSolving #Consistency

Quick update on my Low-Level Design (LLD) practice! I just built a fully thread-safe Parking Lot system in Java. My focus was on writing clean, highly concurrent code using:  👉 𝗔𝘁𝗼𝗺𝗶𝗰 𝗩𝗮𝗿𝗶𝗮𝗯𝗹𝗲𝘀 for lock-free thread safety across multiple gates.    👉 𝗦𝗢𝗟𝗜𝗗 𝗣𝗿𝗶𝗻𝗰𝗶𝗽𝗹𝗲𝘀 to keep components decoupled and easily extensible.    👉 𝗦𝘁𝗿𝗮𝘁𝗲𝗴𝘆 𝗣𝗮𝘁𝘁𝗲𝗿𝗻 for flexible, dynamic payment processing. Great practice in balancing object-oriented design with concurrency constraints! What's your favorite LLD problem to tackle? 👇 Chekout the full code : https://lnkd.in/gkek2jRZ #Java #LowLevelDesign #SoftwareEngineering #Multithreading

Find the minimum distance between a given start index and any occurrence of a target in the array. Leetcode problem link: https://lnkd.in/gZFkirHw 🔍 Key Takeaways: Used a two-pointer approach to scan from both ends. Kept updating the minimum absolute distance from start. Included the condition left != right to avoid checking the same element twice. ✅ Why this works: Instead of scanning only from one side, this approach checks both ends in each iteration, making the logic structured and efficient. 📘 What I like about this solution: Simple and readable Avoids redundant checks Great example of combining two pointers with distance calculation #Java #LeetCode #DSA #Programming #SoftwareEngineering #Developers #loveToCode

Spring Boot Circular Dependency — Dangerous issue ⚠️ Example: Service A → depends on Service B Service B → depends on Service A 👉 Boom 💥 Circular dependency error 💡 Why it happens: Poor design & tight coupling Solutions 👇 ✅ Refactor logic ✅ Use constructor injection properly ✅ Introduce third service ✅ Use @Lazy (temporary fix) ⚠️ Avoid: Field injection (hard to debug) 👉 Best practice: Use constructor injection ALWAYS Clean architecture prevents these issues 🔥 #SpringBoot #Java #CleanCode

I've been working on a small side project for a while, a programming language and compiler. I have just released Siyo Compiler v0.1.0. Siyo compiles directly to JVM bytecode and experiments with stuff like actors, channels, closures, pattern matching, and Java interoperability. The compiler itself is written in Java and currently has a bytecode backend and a small interpreter that I used for testing while building it. Repo: https://lnkd.in/dVNhGfvE Contributions and feedback are welcome.

💻 Great .NET insights from Steven Giesel. This post dives into practical development concepts with clear explanations and real code examples—always a great resource for developers looking to sharpen their skills. 👉 https://lnkd.in/gp8vTSkr #dotnet #SoftwareDevelopment #Programming #DevCommunity

Day 56/100 – LeetCode Challenge Problem: Minimum Cost For Tickets Today I solved the “Minimum Cost For Tickets” problem, which is a dynamic programming problem centered around making optimal decisions over a timeline. The goal is to minimize the total cost of travel tickets by choosing between 1-day, 7-day, and 30-day passes. Instead of making decisions greedily, I approached this by building a DP array where each day represents the minimum cost required up to that point. For each travel day, I considered three possibilities: buying a 1-day pass, a 7-day pass, or a 30-day pass. I then chose the minimum among these options by looking back into previously computed states. For non-travel days, I simply carried forward the previous cost, avoiding unnecessary purchases. This approach ensures that every decision is backed by previously computed optimal results, making the solution both efficient and reliable. The solution runs in O(n) time with O(n) space complexity. This problem reinforced how dynamic programming helps in breaking down decisions over time and choosing the most cost-effective path by evaluating all possible options. Fifty-six days in. The focus is now on making smarter decisions through structured thinking. #100DaysOfLeetCode #Java #DSA #DynamicProgramming #ProblemSolving #Consistency

💥 Stop the NullReferenceException — C# Nullable Reference Types NullReferenceException is the #1 runtime crash in C#. And 99% of the time — it's completely preventable. Here's how to eliminate it 💥 The Problem string name = GetName(); // could be null int len = name.Length; // 💥 CRASH at runtime You won't know it's null until production blows up. ✅ Enable Nullable in C# 8+ Add this to your .csproj: <Nullable>enable</Nullable> Now the compiler warns you before the crash happens. Bugs caught at compile time, not runtime. ❓ string? vs string string name = "Ahmad"; // guaranteed non-null ✅ string? name = null; // explicitly says "this can be null" 🛡️ Null-Safe Operators — Use These Daily user?.Name // null if user is null — no crash name ?? "Anonymous" // fallback if null name ??= "Default" // assign only if null ⚠️ Null Forgiving Operator — Handle with Care string name = GetName()!; // tells compiler "trust me" Use this ONLY when you are 100% certain the value is not null. Otherwise you're just hiding the problem. 💡 Enabling nullable annotations is one of the easiest wins in any C# codebase. It takes 5 minutes to enable and saves hours of debugging. Have you enabled nullable in your projects? #CSharp #DotNet #BackendDevelopment #SoftwareEngineering #CleanCode #Programming #ASPNET