The Code Hut

Understanding Java's object-oriented programming (OOP) concepts is essential for writing clean, reusable, and maintainable code. This post explores classes, objects, OOP principles, functional programming concepts, and key Java features. 1. 🧩 OOP vs Functional Programming OOP: mutable objects, classes, state stored in objects. Functional: immutable, functions as first-class citizens, easy parallelization, fewer bugs. 2. 📦 Classes & Objects Classes are templates for creating objects with fields, methods, and constructors. Objects are instances of classes. 3. 🔑 OOP Principles Abstraction: Hide complex implementation, expose only API. Encapsulation: Hide internal state, control access via private , protected , public . Inheritance: "Is-A" relationship, allows code reuse ( extends ), single inheritance in Java. Polymorphism: Same interface, different implementations. Includes overloading (compile-time) and overriding (runtime). 4...

Writing thread-safe code in Java requires understanding locks, atomic variables, and concurrent utilities. In this post, we'll explore ReentrantLock, synchronized blocks, AtomicLong, LongAdder , and when to use each. 1. 🔑 Synchronized Blocks The simplest way to make a section of code thread-safe is the synchronized keyword. It locks on an object monitor. public class Counter { private int count = 0; public synchronized void increment() { count++; } public synchronized int getCount() { return count; } } ✅ Easy to use for simple critical sections. ❌ Locks the entire object, can reduce concurrency. 2. 🔄 ReentrantLock More flexible than synchronized blocks. Supports tryLock, timed locks, and interruptible locks. import java.util.concurrent.locks.ReentrantLock; ReentrantLock lock = new ReentrantLock(); lock.lock(); try { // critical section } finally { lock.unlock(); } ✅ Better for advanced locking strategies, fair ...

Java provides several map implementations, but not all of them are suitable for multi-threaded environments. Choosing the wrong one can lead to performance bottlenecks, thread-safety issues, or even corrupted data. In this post, we’ll explore the differences between HashMap, Hashtable, and ConcurrentHashMap , explain when to use each, and dive into how ConcurrentHashMap works under the hood. 1. 🗺️ HashMap HashMap is the standard, non-thread-safe map in Java. It allows null keys and values and provides fast lookups with O(1) average time complexity. Map<String, Integer> map = new HashMap<>(); map.put("apple", 1); map.put("banana", 2); Integer value = map.get("apple"); ✅ Fast and memory-efficient for single-threaded applications or maps confined to one thread. ❌ Not safe to use in multiple threads without external synchronization. 2. 🧱 Hashtable Hashtable is a legacy map that is thread-safe because all its methods are s...