Noel KAMPHOA’s Post

Discover how the hashCode method in Java works, its contract with equals, and why proper overriding is crucial for collections.

🚀 Java Revision Journey – Day 25 Today I revised the PriorityQueue in Java, a very important concept for handling data based on priority rather than insertion order. 📝 PriorityQueue Overview A PriorityQueue is a special type of queue where elements are ordered based on their priority instead of the order they are added. 👉 By default, it follows natural ordering (Min-Heap), but we can also define custom priority using a Comparator. 📌 Key Characteristics: • Elements are processed based on priority, not FIFO • Uses a heap data structure internally • Supports standard operations like add(), poll(), and peek() • Automatically resizes as elements are added • Does not allow null elements 💻 Declaration public class PriorityQueue<E> extends AbstractQueue<E> implements Serializable ⚙️ Constructors Default Constructor PriorityQueue<Integer> pq = new PriorityQueue<>(); With Initial Capacity PriorityQueue<Integer> pq = new PriorityQueue<>(10); With Comparator PriorityQueue<Integer> pq = new PriorityQueue<>(Comparator.reverseOrder()); With Capacity + Comparator PriorityQueue<Integer> pq = new PriorityQueue<>(10, Comparator.reverseOrder()); 🔑 Basic Operations Adding Elements: • add() → Inserts element based on priority Removing Elements: • remove() → Removes the highest-priority element • poll() → Removes and returns head (safe, returns null if empty) Accessing Elements: • peek() → Returns the highest-priority element without removing 🔁 Iteration • Can use iterator or loop • ⚠️ Iterator does not guarantee priority order traversal 💡 Key Insight PriorityQueue is widely used in algorithmic problem solving and real-world systems, such as: • Dijkstra’s Algorithm (shortest path) • Prim’s Algorithm (minimum spanning tree) • Task scheduling systems • Problems like maximizing array sum after K negations 📌 Understanding PriorityQueue helps in designing systems where priority-based processing is required, making it essential for DSA and backend development. Continuing to strengthen my Java fundamentals step by step 💪🔥 #Java #JavaLearning #PriorityQueue #DataStructures #JavaDeveloper #BackendDevelopment #Programming #JavaRevisionJourney 🚀

Elevate your coding with 5 Java methods to remove array duplicates while preserving order. Optimize your arrays for maximum efficiency.

Elevate your coding with 5 Java methods to remove array duplicates while preserving order. Optimize your arrays for maximum efficiency.

Learn how to use the this keyword in Java to resolve naming conflicts, enable method chaining, and write clear, maintainable code.

Learn how to use the this keyword in Java to resolve naming conflicts, enable method chaining, and write clear, maintainable code.

Most explanations of Multithreading in Java barely scratch the surface. You’ll often see people talk about "Thread" or "Runnable", and stop there. But in real-world systems, that’s just the starting point—not the actual practice. At its core, multithreading is about running multiple tasks concurrently—leveraging the operating system to execute work across CPU time slices or multiple cores. Think of it like cooking while attending a stand-up meeting. Different tasks, progressing at the same time. In Java, beginners are introduced to: - Extending the "Thread" class - Implementing the "Runnable" interface But here’s the reality: 👉 This is NOT how production systems are built. In company-grade applications, developers rely on the "java.util.concurrent" package and more advanced patterns: 🔹 Thread Pools (Executor Framework) Creating threads manually is expensive. Thread pools reuse a fixed number of threads to efficiently handle many tasks using "ExecutorService". 🔹 Synchronization When multiple threads access shared resources, you must control access to prevent inconsistent data. This is where "synchronized" comes in. 🔹 Locks & ReentrantLock For more control than "synchronized", developers use "ReentrantLock"—allowing manual lock/unlock, try-lock, and better flexibility. 🔹 Race Conditions One of the biggest problems in multithreading. When multiple threads modify shared data at the same time, results become unpredictable. 🔹 Thread Communication (Condition) Threads don’t just run—they coordinate. Using "Condition", "wait()", and "notify()", threads can signal each other and work together. --- 💡 Bottom line: Multithreading is not just about creating threads. It’s about managing concurrency safely, efficiently, and predictably. That’s the difference between writing code… and building scalable systems. #Java #Multithreading #BackendEngineering #SoftwareEngineering #Concurrency #Tech

I recently explored a subtle but important concept in Java constructor execution order. Many developers assume constructors simply initialize values, but the actual lifecycle is more complex. In this article, I explain: • The real order of object creation • Why overridden methods can behave unexpectedly • A common bug caused by partial initialization This concept is especially useful for interviews and writing safer object-oriented code. Medium Link: https://lnkd.in/gtRhpdfP #Java #OOP #SoftwareDevelopment #Programming

Discover the differences between Stack and Heap in Java: how memory is allocated, managed, and used for variables, objects, and method calls.

Discover the differences between Stack and Heap in Java: how memory is allocated, managed, and used for variables, objects, and method calls.