Samsung Senior Software Engineer Interview Questions and Answers

Creating a new Android service

• Define a class that extends Service class

• Override onStartCommand() method to handle service logic

• Register the service in AndroidManifest.xml file

Managing gralloc buffers involves allocating, locking, and freeing memory for graphics rendering in Android.

• Allocate gralloc buffer using gralloc_alloc() function

• Lock buffer for reading or writing using gralloc_lock() function

• Free buffer using gralloc_free() function

• Example: gralloc_alloc(usage, width, height, format, &handle)

• Example: gralloc_lock(handle, usage, left, top, width, height, &vaddr)

HIDL stands for Hardware Interface Definition Language and is used for communication between HAL and framework. AIDL stands for Android Interface Definition Language and is used for inter-process communication in Android.

• HIDL is used for communication between Hardware Abstraction Layer (HAL) and framework in Android

• AIDL is used for inter-process communication in Android

• HIDL is more efficient and faster than AIDL

Android buffers are passed from application to drivers through shared memory and buffer queues.

• Android applications communicate with drivers through the HAL (Hardware Abstraction Layer)

• Buffers are typically passed using shared memory regions

• Buffer queues are used to manage the flow of data between application and driver

• Example: Camera application passing image data to camera driver for processing

When LINUX faces a hardware interrupt, it stops executing the current code and jumps to a specific interrupt handler.

• LINUX stops executing the current code and jumps to a specific interrupt handler

• The interrupt handler processes the interrupt and resumes normal execution afterwards

• Different hardware interrupts are handled by different interrupt handlers

The challenge while creating multiple services in Android is managing communication between services and ensuring proper synchronization.

• Managing communication between services can be complex and error-prone.

• Ensuring proper synchronization between services to avoid race conditions and data inconsistencies.

• Handling dependencies between services and coordinating their interactions.

• Testing and debugging multiple services ...read more

The Android boot up sequence involves several stages including power on, bootloader, kernel initialization, system server startup, and app launch.

• Power on the device

• Bootloader loads the Android OS kernel

• Kernel initializes the system and drivers

• System server starts up and launches essential services

• Apps are launched and user interface becomes accessible

Permission files/SE Linux policy control access to resources based on rules set by administrators.

• Permission files define who can access a file or directory and what actions they can perform.

• SE Linux policy is a security mechanism that enforces rules on how processes interact with resources.

• SE Linux policy is based on labels assigned to processes and resources, determining access permissions.

• SE Linux policy can be cust...read more

A manifestation file is a configuration file used to define the properties and settings of a software application.

• Manifestation files typically include information such as the application's name, version, dependencies, and permissions.

• They are commonly used in software development to ensure that the application runs correctly and has access to necessary resources.

• Examples of manifestation files include AndroidManifest....read more

Designing an OTT platform involves user management, content delivery, and scalability considerations.

• User Management: Implement user authentication and profiles, e.g., Netflix accounts.

• Content Delivery: Use CDNs for efficient streaming, e.g., Akamai or Cloudflare.

• Scalability: Design for high traffic with microservices architecture, e.g., AWS Lambda.

• Content Management: Build a CMS for uploading and managing videos, e.g....read more

Calculate the amount of rainwater that can be trapped between the bars of varying heights after rainfall.

• Use two pointers to traverse the array from both ends towards the center.

• Maintain two variables to track the maximum height from the left and right.

• At each step, calculate trapped water based on the minimum of the two maximum heights.

• Example: For heights [0,1,0,2,1,0,1,3,2,1,2,1], the trapped water is 6.