Top 30 Kotlin Interview Questions — From Basics to Coroutines
The 30 most commonly asked Kotlin interview questions with clear answers and code examples. Covers basics (val/var, null safety, string interpolation)...
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ANDROID 16 IS QUIET — BUT ONE OF THE MOST IMPORTANT RELEASES FOR DEVELOPERS
Android 16 (API level 36) is less about new UI features and more about making app behavior predictable and reliable. It introduces refinements in navi...
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DNS Spoofing Testing on Android — What It Is, Why It Matters, and 4 Hands-On Lab Approaches
When your app calls api.mybank.com, who decides which IP that resolves to? On compromised Wi-Fi, the attacker controls DNS and points your domain at t...
Kotlin Coroutines & Flow from First Principles — The Complete Mental Model for Android
This is the post I wish existed when I started using coroutines. Not the API docs — those are fine. What I needed was the mental model: why does...
Kotlin Coroutines & Flow in Production — The 10 Anti-Patterns That Ship and How to Fix Them
The footgun-to-insight ratio with coroutines is unusually high. The API is small; the ways to misuse it are many; the bugs are subtle and pass code re...
Why Your Push Notifications Work on Pixel and Fail on Xiaomi — FCM Across OEMs
I don't get notifications until I open the app. Then they all arrive at once. My friend on iPhone gets them instantly. Your app is broken." The user i...
Secure File Upload on Android — Chunked, Resumable, Encrypted Uploads for Banking & Enterprise Apps
Upload a file" sounds basic, and the tutorials treat it that way: build a MultipartBody.Part, hand it to Retrofit, done. Then you ship it to a banking...
Google Maps SDK on Android — Implementation Deep-Dive Beyond the Tutorials
The Google Maps tutorials online stop at exactly the wrong place — drop a map, add one marker, done. They don't teach what happens when you buil...
OEM Battery Optimization Killing Your App — A Survival Guide for Samsung, Xiaomi, Huawei, and the ColorOS Family
The fitness app stops counting my steps after a few hours. Started happening on my new Samsung — my old Pixel was fine." The user thinks the app...
Android Root & Tampering Detection — Play Integrity, RootBeer, and the Cat-and-Mouse Reality
Root detection on Android is a cat-and-mouse game where the cat keeps losing. Every check you write, someone has a Magisk module that defeats it. Ever...
Android Security for Banking & Enterprise Apps — Threat Model, Keystore, Cert Pinning, and the OEM Realities
The first time I worked on a banking app, I learned the threat model is fundamentally different. Consumer apps protect against bugs; banking apps prot...
System Design — Design Uber / Ride Sharing (Time-Scale Tiers and Spatial Real-Time Matching)
"Design Uber" is the first system design problem where real-time location is central. WhatsApp is about delivering bytes; Instagram is about choosing ...
Android Memory & Performance Interview Questions — 17 Investigation-Driven Prompts for Senior Roles
The performance round at a senior Android interview is rarely "define jank." It's "your app drops to 30fps when scrolling — walk me through your...
Android Architecture Interview Questions — 20 Scenario-Driven Prompts for Senior Roles
The architecture round is where most senior Android interviews are won or lost. The reason: architecture questions don't have textbook answers. "What ...