What is JIT?

Experience Level: Senior


Quick introduction

Before a computer can execute the application, special program that is called compiler must translate its source code into machine instructions.

The compilation can be done either Ahead-Of-Time (AOT) or Just-In-Time (JIT).

So JIT = Just-In-Time

By default .NET uses JIT compiler. It is a part of CLR (Common Language Runtime). The CLR manages the execution of .NET applications.

Compiler types

  • AOT - Ahead-Of-Time (Explicit) - compiles the code prior to program executio
  • JIT - Just-In-Time (Implicit) - compiles the code on-demand

Good to know

  • Output of JIT is not persisted so your managed application has to go through JIT for every launch.
  • Pre-compilation (using NGEN) can be used to reduce startup overheads related with JIT compilation



No Comments Yet.
Be the first to tell us what you think.
.NET challenge
.NET challenge

Are you learning C# ? Try our test we designed to help you progress faster.

Test yourself