Mohibul Hassan

An honest retrospective on a challenge that did not happen in a clean streak, and on how learning Java slowly turned into learning how systems behave.

After Day 98, I thought virtual threads replaced event loops.

I added .parallel() expecting near-linear speedup on 8 cores.

Deep dive into Java 21 Virtual Threads implementation - from continuations and heap-based stacks to mount/unmount mechanics, pinning problems, and production trade-offs.

Advanced Java concurrency - DelayQueue, ReentrantLock, Phaser with debugging techniques, monitoring patterns, and production readiness checklist.

Master core Java concurrency synchronization - CyclicBarrier, Semaphore, ThreadFactory, and BlockingQueue with production patterns, trade-offs, and real-world examples.

Master the foundation of Java concurrency - Executor, ExecutorService, ScheduledExecutorService, Future, CompletableFuture, and CountDownLatch with production patterns, trade-offs, and debugging techniques.

Your Java app takes so much time to start.

Building a @Sensitive annotation with annotation processor to mask sensitive data in logs and stack traces - Java's answer to PHP's #[SensitiveParameter]

Learn to build intelligent Java AI applications using Spring AI framework.

Ever wondered how to process gigabyte-sized files without crashing your JVM?

Ever wondered how APM tools like New Relic spy on your Java applications?

That perfect Singleton you wrote?

Leveraging Google Cloud Vertex AI's Gemini 1.5 for advanced, multilingual audio transcription within a Spring Boot application, including prompt engineering, safety settings management, and confidence scoring.

Day 87: Java's Environment Variable Paradox: Easy to Read, Impossible to Change?

Day 86: Building a Secure Java Sandbox with Custom Class Loaders, Process isolation and Java Platform Module System

Day 85: Idempotent APIs in Java: Concepts, Implementation Strategies, and a Spring Boot File Upload Implementation

Day 84: Hot Class Reload in Java – A Webpack HMR-like Experience for Java Developers using WatchService and Javax.tools api

Day 83: Java Object Cloning: Exploring Shallow and Deep Copy Techniques

Day 82: Reflection in Java: Building a Simple DI Container in 100 Lines of Code

Day 81: Creating custom stream operations ex: Slide, Shift, Zip and Fold using Spliterator

Day 80: From Concept to Code: Implementing a Dummy Consistent Hashing in Java using TreeMap

Day 79: Did you know that too much print statement can cost you money

Day 78: Java 22 - Embracing Safe Memory Allocation Using MemorySegment and Arena API - An alternative to Unsafe API

Explore Something Unsafe : Crafting a Memory allocator using Java Unsafe API

Implementing a dummy Service Oriented Architecture (SOA) service to Understand Java SPI

Java Buffered Reader and why we need to close and what will happend if we dont

Java Security: Crafting a toy TLS Server with Java Security API

Java Security: Safeguarding Data with Encryption and Keys

Can a HashMap Take Null or Empty String as a Key in Java?

Understanding Heap poullion in java and its causes and how to prevent it.

Measuring the performance of different array copying methods in Java using JMH

Exploring benchmarking harness in Java and how its use to understand performance

Finding memory leak by analyzing GC and memory dump using VisualVM and Eclipse MAT

Finding memory leak by analyzing GC and memory dump using VisualVM and Eclipse MAT

Finding memory leak by analyzing GC and memory dump using VisualVM and Eclipse MAT

Understanding how RPC and RMI works in java

Implementing a basic bloom filter to understand its concepts and usages using Java BitSet api

Using JMX to write an alert system for Java JVM OutOfMemory Error

Understanding JMX architecture and how it works.

Understanding JMX architecture and how it works.

Generating Heap dumps programatically by using MBeanServer and PlatformBeans to get Management information from JVM

Understanding Proxy and Dynamic Proxy in Java

Mocking void methods using ArgumentCapture and Answering

Understanding details and compare use cases of Random, ThreadLocalRandom and SecureRandom

What is zero length Array and why its in java and how its used

Blue-Green Deployment using DNS to reduce downtime of production application

Understanding java classe's static and instance initializer

git troubleshooting with helpful commands to revert, stash, split, recover commits

Understanding volatile keyword's use in incrementing a double variable and see how it behaves in multi threaded env