Introduction

This post provides a comprehensive list of Android and native system design interview questions for Meta’s Senior Software Engineer positions. These questions focus on Android architecture, native code integration, performance optimization, and system-level design challenges.

Note: This is distinct from OS Frameworks questions - these focus on Android application architecture, native libraries, and system design for Android platforms at Meta scale.

Meta Android/Native System Design Interview Overview

Interview Format

  • Duration: 45 minutes
  • Format: System design interview (Pirate Interview)
  • Focus: Android architecture, native systems, performance at scale
  • Process: Discussion and whiteboarding/virtual board
  • Evaluation: Problem-solving, technical depth, Android expertise

Key Evaluation Areas

  1. Android Architecture Knowledge: Understanding of Android framework, components, and architecture
  2. Native Code Integration: JNI, NDK, C/C++ integration
  3. Performance Optimization: Memory, CPU, battery, network optimization
  4. Scalability: Designing for millions of Android users
  5. System Design: Overall system architecture and component design

Common Android/Native System Design Questions

Android Application Architecture Questions (Highest Priority)

These questions focus on designing Android applications and their architecture.

1. Design an Android News Feed App (Instagram Feed)

Key Features:

  • Scrollable feed of photos/videos
  • Infinite scrolling
  • Image loading and caching
  • Like and comment interactions
  • Real-time updates

Challenges:

  • Efficient image loading and caching
  • Memory management for images
  • Smooth scrolling performance
  • Offline support
  • Battery optimization
  • Network usage optimization

Key Components:

  • Image loading library (Glide/Coil)
  • Caching strategy (memory + disk)
  • RecyclerView optimization
  • Network layer (Retrofit/OkHttp)
  • Database layer (Room)

2. Design an Android Messaging App (WhatsApp/Instagram DM)

Key Features:

  • Real-time messaging
  • Message persistence
  • Media sharing (images, videos, files)
  • Read receipts and typing indicators
  • Push notifications
  • End-to-end encryption

Challenges:

  • Real-time message synchronization
  • Offline message queuing
  • Media upload/download optimization
  • Battery-efficient background sync
  • Encryption key management
  • Message ordering and consistency

Key Components:

  • WebSocket/connection management
  • Message database (Room)
  • Media upload service
  • Push notification service
  • Encryption layer

3. Design an Android Video Streaming App (Instagram Reels/Stories)

Key Features:

  • Video playback and streaming
  • Video upload
  • Video processing and transcoding
  • Adaptive bitrate streaming
  • Video caching
  • Background playback

Challenges:

  • Video streaming optimization
  • Adaptive bitrate selection
  • Memory management for video
  • Battery optimization
  • Network bandwidth management
  • Video transcoding pipeline

Key Components:

  • Video player (ExoPlayer)
  • CDN integration
  • Video caching
  • Adaptive streaming logic
  • Upload service

4. Design an Android Camera App

Key Features:

  • Photo and video capture
  • Real-time filters and effects
  • Image processing
  • Camera preview
  • Media storage
  • Sharing functionality

Challenges:

  • Camera API management
  • Real-time image processing
  • Memory management for images
  • Battery optimization
  • Performance optimization
  • Native code integration for image processing

Key Components:

  • Camera2/CameraX API
  • Image processing pipeline (native)
  • Media storage
  • Filter library
  • Preview rendering

5. Design an Android Location-Based App

Key Features:

  • Location tracking
  • Geofencing
  • Location-based notifications
  • Map display
  • Location history
  • Battery-efficient location updates

Challenges:

  • Battery optimization for GPS
  • Location accuracy vs. power consumption
  • Background location tracking
  • Geofencing implementation
  • Location data privacy

Key Components:

  • Location services (Fused Location Provider)
  • Geofencing service
  • Background location service
  • Map SDK integration
  • Location database

Native Code Integration Questions (High Priority)

These questions focus on integrating native code (C/C++) with Android applications.

6. Design a Native Image Processing Library

Key Features:

  • Image filters and effects
  • Image compression
  • Image format conversion
  • Real-time processing
  • Batch processing

Challenges:

  • JNI bridge design
  • Memory management across boundaries
  • Performance optimization
  • Thread safety
  • Error handling

Key Components:

  • Native C/C++ library
  • JNI bridge
  • Memory management
  • Thread pool
  • Error handling layer

7. Design a Native Audio Processing System

Key Features:

  • Audio recording and playback
  • Audio effects and filters
  • Real-time audio processing
  • Audio format conversion
  • Low-latency audio

Challenges:

  • Real-time processing constraints
  • Low-latency requirements
  • Audio buffer management
  • Thread synchronization
  • Native code optimization

Key Components:

  • Native audio library
  • JNI interface
  • Audio buffers
  • Thread management
  • Audio effects pipeline

8. Design a Native Machine Learning Inference Engine

Key Features:

  • ML model inference
  • Model optimization
  • Batch and real-time inference
  • Model versioning
  • Performance optimization

Challenges:

  • Model loading and caching
  • Memory management for models
  • Inference performance
  • Model quantization
  • Thread safety

Key Components:

  • Native ML library (TensorFlow Lite, ONNX)
  • JNI bridge
  • Model cache
  • Inference pipeline
  • Performance monitor

9. Design a Native Video Codec System

Key Features:

  • Video encoding/decoding
  • Multiple codec support (H.264, H.265, VP9)
  • Hardware acceleration
  • Adaptive bitrate encoding
  • Real-time encoding

Challenges:

  • Hardware codec integration
  • Software codec fallback
  • Memory management
  • Performance optimization
  • Codec compatibility

Key Components:

  • MediaCodec API
  • Native codec library
  • Hardware acceleration layer
  • Memory management
  • Codec abstraction

Performance and Optimization Questions (High Priority)

These questions focus on optimizing Android applications for performance.

10. Design an Android App Performance Monitoring System

Key Features:

  • Real-time performance metrics
  • CPU, memory, network monitoring
  • Crash reporting
  • Performance profiling
  • Battery usage tracking

Challenges:

  • Minimal performance overhead
  • Real-time data collection
  • Data aggregation and storage
  • Battery impact
  • Privacy considerations

Key Components:

  • Performance monitoring SDK
  • Native profilers
  • Data collection service
  • Analytics service
  • Crash reporting

11. Design an Android Memory Management System

Key Features:

  • Memory leak detection
  • Memory profiling
  • Automatic memory optimization
  • Low memory handling
  • Memory usage tracking

Challenges:

  • Detecting memory leaks
  • Memory profiling overhead
  • Automatic optimization
  • Low memory scenarios
  • Performance impact

Key Components:

  • Memory profiler
  • Leak detection
  • Memory allocator
  • GC optimization
  • Memory monitoring

12. Design an Android Battery Optimization System

Key Features:

  • Battery usage tracking
  • Background task optimization
  • Wake lock management
  • Doze mode compatibility
  • Battery-aware scheduling

Challenges:

  • Battery usage analysis
  • Background task optimization
  • Wake lock management
  • Doze mode handling
  • Battery impact minimization

Key Components:

  • Battery monitor
  • Background task scheduler
  • Wake lock manager
  • Doze mode handler
  • Optimization engine

Android System Integration Questions (Medium Priority)

These questions focus on Android system-level integration and services.

13. Design an Android Background Task System

Key Features:

  • Background task scheduling
  • Task priorities and constraints
  • Battery optimization
  • Work scheduling across Android versions
  • Task persistence and recovery

Challenges:

  • WorkManager vs. JobScheduler
  • Battery optimization compatibility
  • Task persistence
  • Android version compatibility
  • Performance optimization

Key Components:

  • Task scheduler
  • WorkManager/JobScheduler
  • Battery optimization handler
  • Task queue
  • Persistence layer

14. Design an Android Push Notification System

Key Features:

  • Push notifications delivery
  • Notification channels and priorities
  • Rich notifications
  • Notification actions
  • Delivery tracking

Challenges:

  • FCM/APNs integration
  • Notification delivery reliability
  • Battery optimization
  • Notification grouping
  • User preferences

Key Components:

  • Push notification service
  • FCM/APNs integration
  • Notification manager
  • Delivery tracking
  • User preferences

15. Design an Android Offline-First App Architecture

Key Features:

  • Offline data storage
  • Sync mechanism
  • Conflict resolution
  • Offline-first UI
  • Data synchronization

Challenges:

  • Local database design
  • Sync strategy
  • Conflict resolution
  • Network state handling
  • Data consistency

Key Components:

  • Local database (Room)
  • Sync service
  • Conflict resolver
  • Network state monitor
  • Data repository

Native System Architecture Questions (Medium Priority)

These questions focus on native system architecture and design.

16. Design a Native Thread Pool System

Key Features:

  • Thread pool management
  • Task scheduling
  • Priority management
  • Thread lifecycle management
  • Performance optimization

Challenges:

  • Thread pool sizing
  • Task scheduling algorithms
  • Thread synchronization
  • Resource management
  • Performance optimization

Key Components:

  • Thread pool manager
  • Task queue
  • Scheduler
  • Thread lifecycle manager
  • Performance monitor

17. Design a Native Memory Allocator

Key Features:

  • Custom memory allocation
  • Memory pool management
  • Memory leak detection
  • Performance optimization
  • Memory fragmentation handling

Challenges:

  • Allocation performance
  • Memory fragmentation
  • Memory leak detection
  • Thread safety
  • Memory alignment

Key Components:

  • Memory allocator
  • Memory pool
  • Leak detector
  • Performance monitor
  • Thread-safe wrappers

18. Design a Native IPC System

Key Features:

  • Inter-process communication
  • Message passing
  • Shared memory
  • Synchronization
  • Performance optimization

Challenges:

  • IPC mechanism selection
  • Message serialization
  • Synchronization
  • Performance optimization
  • Error handling

Key Components:

  • IPC mechanism (Binder, sockets, shared memory)
  • Message serializer
  • Synchronization primitives
  • Error handler
  • Performance monitor

Android Framework Integration Questions (Lower Priority)

19. Design an Android Custom View System

Key Features:

  • Custom view components
  • View rendering optimization
  • Touch event handling
  • Animation system
  • Performance optimization

Challenges:

  • View rendering performance
  • Touch event handling
  • Animation smoothness
  • Memory management
  • Battery optimization

20. Design an Android Plugin System

Key Features:

  • Dynamic plugin loading
  • Plugin isolation
  • Plugin communication
  • Plugin lifecycle
  • Security

Challenges:

  • Dynamic loading
  • Plugin isolation
  • Communication mechanism
  • Lifecycle management
  • Security sandboxing

21. Design an Android Build System Integration

Key Features:

  • Gradle build integration
  • Native code compilation
  • Dependency management
  • Build optimization
  • CI/CD integration

Challenges:

  • Build performance
  • Native code compilation
  • Dependency management
  • Build caching
  • Incremental builds

Question Categories by Frequency

Tier 1: Most Common Questions (Must Practice)

These questions appear in 60%+ of Meta Android/native interviews:

  1. Design an Android News Feed App (#1)
  2. Design an Android Messaging App (#2)
  3. Design a Native Image Processing Library (#6)
  4. Design an Android Video Streaming App (#3)
  5. Design an Android App Performance Monitoring System (#10)

Tier 2: Very Common Questions (High Priority)

These questions appear in 40-60% of interviews:

  1. Design an Android Camera App (#4)
  2. Design an Android Location-Based App (#5)
  3. Design a Native Audio Processing System (#7)
  4. Design an Android Memory Management System (#11)
  5. Design an Android Battery Optimization System (#12)

Tier 3: Common Questions (Medium Priority)

These questions appear in 20-40% of interviews:

  1. Design a Native Machine Learning Inference Engine (#8)
  2. Design a Native Video Codec System (#9)
  3. Design an Android Background Task System (#13)
  4. Design an Android Push Notification System (#14)
  5. Design an Android Offline-First App Architecture (#15)

Tier 4: Less Common Questions (Lower Priority)

These questions appear in 10-20% of interviews:

  1. Design a Native Thread Pool System (#16)
  2. Design a Native Memory Allocator (#17)
  3. Design a Native IPC System (#18)
  4. Design an Android Custom View System (#19)
  5. Design an Android Plugin System (#20)
  6. Design an Android Build System Integration (#21)

Android-Specific Design Patterns

Pattern 1: Android Architecture Components

  • MVVM (Model-View-ViewModel)
  • Repository Pattern
  • Dependency Injection
  • LiveData / Flow
  • Room Database

Pattern 2: Performance Optimization

  • Image Loading and Caching
  • RecyclerView Optimization
  • Memory Management
  • Battery Optimization
  • Network Optimization

Pattern 3: Native Code Integration

  • JNI Bridge Design
  • NDK Integration
  • Memory Management
  • Thread Safety
  • Error Handling

Pattern 4: Real-Time Systems

  • WebSocket Connections
  • Push Notifications
  • Background Sync
  • Real-Time Updates
  • Offline Support

Key Android Concepts to Master

Android Architecture

  • Android Framework: Activities, Services, BroadcastReceivers, ContentProviders
  • Lifecycle Management: Activity lifecycle, Service lifecycle, Fragment lifecycle
  • Android Jetpack: ViewModel, LiveData, Room, Navigation, WorkManager
  • Dependency Injection: Dagger/Hilt, Koin
  • Architecture Patterns: MVVM, MVP, MVI, Clean Architecture

Native Code Integration

  • JNI (Java Native Interface): Bridge between Java and native code
  • NDK (Native Development Kit): Tools for native development
  • CMake: Build system for native code
  • ABI (Application Binary Interface): ARM, x86, x86_64, ARM64
  • Native Libraries: Integration and optimization

Performance Optimization

  • Memory Management: Heap, garbage collection, memory leaks
  • CPU Optimization: Threading, async processing, algorithm optimization
  • Battery Optimization: Background tasks, wake locks, Doze mode
  • Network Optimization: Request batching, caching, compression
  • UI Optimization: RecyclerView, View rendering, animation

Android System Services

  • Location Services: GPS, network location, geofencing
  • Camera Services: Camera2, CameraX, image processing
  • Media Services: MediaPlayer, ExoPlayer, MediaCodec
  • Notification Services: NotificationManager, FCM
  • Storage Services: SharedPreferences, Room, File storage

Meta-Specific Android Considerations

Scale Expectations

  • Users: Millions to billions of Android users
  • Devices: Diverse Android devices and versions
  • Performance: Smooth 60 FPS UI
  • Battery: Minimal battery impact
  • Network: Efficient data usage

Technology Stack

Meta commonly uses for Android:

  • Languages: Kotlin, Java, C++
  • Architecture: MVVM, Clean Architecture
  • Networking: Retrofit, OkHttp
  • Database: Room, SQLite
  • Dependency Injection: Dagger/Hilt
  • Image Loading: Glide, Coil
  • Reactive: RxJava, Coroutines/Flow

Meta Android Products

  • Facebook Android App: Core Facebook experience
  • Instagram Android App: Photo/video sharing
  • WhatsApp Android App: Messaging
  • Messenger Android App: Chat and calls
  • Meta Business Apps: Business tools

How to Use This List

Preparation Strategy

  1. Start with Tier 1 Questions
    • Master Android application architecture
    • Understand native code integration
    • Practice performance optimization
  2. Practice Tier 2 Questions
    • Cover Android-specific features
    • Understand system integration
    • Practice optimization techniques
  3. Review Tier 3 & 4 Questions
    • Familiarize with advanced topics
    • Understand native systems
    • Know when to apply them

Practice Approach

For each question, practice:

  1. Problem Navigation
    • Clarify Android-specific requirements
    • Understand device constraints
    • Consider Android versions
    • Identify performance requirements
  2. Solution Design
    • Android architecture components
    • Native code integration
    • Performance optimization strategies
    • Battery optimization considerations
  3. Technical Excellence
    • Detailed component design
    • Native code architecture
    • Performance optimization techniques
    • Trade-offs analysis
  4. Technical Communication
    • Explain Android architecture choices
    • Discuss native code integration
    • Address performance considerations
    • Discuss Android-specific challenges

Interview Tips

  1. Android-Specific Considerations
    • Consider Android versions and compatibility
    • Think about device diversity
    • Consider battery and performance
    • Understand Android lifecycle
  2. Native Code Integration
    • JNI bridge design
    • Memory management
    • Thread safety
    • Error handling
  3. Performance First
    • Always consider performance
    • Memory optimization
    • Battery optimization
    • Network optimization
  4. Show Android Expertise
    • Demonstrate deep Android knowledge
    • Show understanding of Android internals
    • Discuss Android best practices
    • Address Android-specific challenges

Conclusion

This list provides a comprehensive overview of Android and native system design questions for Meta Senior Software Engineer positions. Remember:

  • Focus on Android architecture (MVVM, Jetpack, Clean Architecture)
  • Master native code integration (JNI, NDK, performance)
  • Prioritize performance (memory, battery, network optimization)
  • Think at Meta scale (millions of users, diverse devices)
  • Show Android expertise (deep understanding of Android internals)

Key Success Factors:

  1. Strong Android architecture knowledge
  2. Native code integration expertise
  3. Performance optimization skills
  4. Battery optimization awareness
  5. Understanding of Android system internals

Good luck with your Meta Android/native system design interview preparation!