To answer the interview question "What is the difference between AppDomain, Assembly, Process, and a Thread?" in the context of .NET Core, here is a detailed explanation:
AppDomain
An AppDomain (Application Domain) is an isolation unit within a process. It provides a layer of isolation for executing managed code, allowing multiple applications to run within a single process without affecting each other. AppDomains can be created at runtime, loaded with code, and unloaded. They are designed to make .NET applications more reliable by isolating faults and enabling secure execution of code. However, it's important to note that in .NET Core, the concept of AppDomains has been largely deprecated and replaced by other mechanisms such as AssemblyLoadContext for dynamic assembly loading and process isolation for code isolation[1][2][8][11].
Assembly
An Assembly is a compiled code library used for deployment, versioning, and security in .NET applications. It is the fundamental unit of deployment and version control in .NET. Assemblies can be either executable files (.EXE) or dynamic link libraries (.DLL). They contain one or more modules, which in turn contain compiled code, metadata, and resources. Assemblies are loaded into an AppDomain and provide the common language runtime (CLR) with the information it needs to execute the code[1][2][12][18].
Process
A Process is an instance of a running application. It is an executing program that has its own memory space, including a stack, heap, and data segments. Each process is isolated from other processes, meaning that one process cannot directly access the memory of another process. Processes are managed by the operating system, which allocates resources and schedules their execution. In .NET, a process can host multiple AppDomains (in .NET Framework) or use other isolation mechanisms in .NET Core[1][2][3][4][5].
Thread
A Thread is the smallest unit of execution within a process. It is a path of execution that runs within the context of a process. Threads share the same memory space of the process but have their own stack and registers. Multiple threads can run concurrently within a single process, allowing for parallel execution of code. Threads are managed by the operating system, which performs context switching to give the appearance of simultaneous execution. Threads are considered lightweight compared to processes because they share resources and have lower overhead fo...
