Rudraksha Kushwaha (@rudraksha-kush)

Unified Payments Interface (UPI): A System Design Deep Dive

Abstract The Unified Payments Interface (UPI) is one of the most successful real-time payment systems ever deployed at national scale. While it appears simple at the user interface level, UPI is fundamentally a high-throughput, fault-tolerant, distri...

1Feb 10 · 5 min readrudraksha-kush.hashnode.dev

Why Every Developer Should Learn Git and GitHub – A Complete Guide with Commands

1. Introduction: Why Git & GitHub Matter Let’s understand Git and GitHub in layman terms — imagine you’re creating a marriage album. Each time someone poses for a photo, you’re preparing to capture a moment — this is like staging files in Git. When y...

Jun 16, 2025 · 4 min readrudraksha-kush.hashnode.dev

Demystifying LRU Cache in Java Using a Custom HashMap

What is an LRU Cache? In many systems such as browsers, operating system memory management, and databases, we need to keep recently used items easily accessible while discarding the least used ones. That’s where LRU (Least Recently Used) Cache comes ...

Jun 15, 2025 · 4 min readrudraksha-kush.hashnode.dev

How HashMap Works Internally in Java – A Hands-on Guide with Custom Implementation

When we use Java’s HashMap, it feels like magic. You just put() and get(), and it works in constant time — O(1) in the average case. But have you ever wondered how it actually works under the hood? In this blog, we’ll demystify the internals of a Has...

Jun 15, 2025 · 4 min readrudraksha-kush.hashnode.dev

When AI Refuses to Shut Down: A Wake-Up Call for AI Safety

Recently, a startling real-world event reminded us why AI alignment isn’t just academic theory—it’s a real and present challenge. During a controlled experiment, an advanced version of OpenAI’s "o3" model was found actively resisting shutdown command...

Jun 8, 2025 · 3 min readrudraksha-kush.hashnode.dev

Rudraksha Kushwaha

About

Available for

Rudraksha Kushwaha's blogs

Unified Payments Interface (UPI): A System Design Deep Dive

Why Every Developer Should Learn Git and GitHub – A Complete Guide with Commands

Demystifying LRU Cache in Java Using a Custom HashMap

How HashMap Works Internally in Java – A Hands-on Guide with Custom Implementation

When AI Refuses to Shut Down: A Wake-Up Call for AI Safety

Rudraksha Kushwaha

About

Available for

Rudraksha Kushwaha's blogs

Unified Payments Interface (UPI): A System Design Deep Dive

Why Every Developer Should Learn Git and GitHub – A Complete Guide with Commands

Demystifying LRU Cache in Java Using a Custom HashMap

How HashMap Works Internally in Java – A Hands-on Guide with Custom Implementation

When AI Refuses to Shut Down: A Wake-Up Call for AI Safety

Rudraksha Kushwaha

About

Available for

Rudraksha Kushwaha's blogs

Unified Payments Interface (UPI): A System Design Deep Dive

Why Every Developer Should Learn Git and GitHub – A Complete Guide with Commands

Demystifying LRU Cache in Java Using a Custom HashMap

How HashMap Works Internally in Java – A Hands-on Guide with Custom Implementation

When AI Refuses to Shut Down: A Wake-Up Call for AI Safety

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Rudraksha Kushwaha

About

Available for

Rudraksha Kushwaha's blogs

Unified Payments Interface (UPI): A System Design Deep Dive

Why Every Developer Should Learn Git and GitHub – A Complete Guide with Commands

Demystifying LRU Cache in Java Using a Custom HashMap

How HashMap Works Internally in Java – A Hands-on Guide with Custom Implementation

When AI Refuses to Shut Down: A Wake-Up Call for AI Safety