Android Interview Series 2026 Cheat Sheet — Part 8

Let’s start with the basics: What is an Application in Android? The Application class is the base class within an Android app that contains all other components, such as activities and services. It’s instantiated before any other class when your app’s process is created. This means it’s the foundation for everything else in your app, ensuring all components have a common context and can interact seamlessly. Understanding this helps you manage global state and resources efficiently. 00:36 Next, let’s talk about Context. In Android, Context is a handle to the system, providing services like resource resolution, database access, and more. There are two main types: Application Context, which is tied to the app’s lifecycle, and Activity Context, which is tied to a specific activity’s lifecycle. Knowing when to use each is crucial for avoiding memory leaks and ensuring your app behaves as expected. 00:54 Android supports several CPU architectures, with ARMv7 being the most common due to its battery efficiency. ARM64 is a more powerful, 64-bit version, while x86 is less common but offers strong performance. Understanding these architectures helps you optimize your app for different devices and ensure compatibility across the Android ecosystem. 01:11 Why can’t Android run standard Java bytecode? Android uses the Dalvik Virtual Machine (DVM) instead of the Java Virtual Machine (JVM). Dalvik is optimized for mobile devices, focusing on low memory usage and battery efficiency. This difference is key to understanding how Android executes code and why APKs are structured the way they are. 01:28 Gradle build types define how your app is built and packaged. For example, you can specify whether ProGuard runs, or which resources are included. Gradle combines build types and product flavors to create build variants, giving you flexibility for different environments like development, staging, and production. Mastering build types helps you streamline your release process. 01:45 The Android build process involves several steps. First, resources are compiled into the R.java file. Next, Java source code is compiled to .class files, then converted to Dalvik bytecode (.dex) using the dx tool. Finally, the apkbuilder packages everything into the APK file. Understanding this process helps you troubleshoot build issues and optimize your app’s performance. 02:02 Android application architecture is made up of several components: Services for background tasks, Intents for communication, Resource Externalization for managing strings and graphics, Notifications for user alerts, and Content Providers for sharing data. Each plays a unique role in building robust, modular apps. 02:18 Activities are the main entry points for user interaction in Android. Think of them as windows or containers for your app’s UI. Each activity represents a single screen, and you can have multiple activities in an app, each handling different tasks or workflows.