What is JIT and how is works ?

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What is JIT and how is works ?..

Answer / alb.shah

When compiling the source code to managed code, the
compiler translates the source into Microsoft intermediate
language

(MSIL). This is a CPU-independent set of instructions that
can efficiently be converted to native code. Microsoft

intermediate language (MSIL) is a translation used as the
output of a number of compilers. It is the input to a just-
in-time

(JIT) compiler. The Common Language Runtime includes a JIT
compiler for the conversion of MSIL to native code.

Before Microsoft Intermediate Language (MSIL) can be
executed it, must be converted by the .NET Framework just-
in-time (JIT)

compiler to native code. This is CPU-specific code that
runs on the same computer architecture as the JIT compiler.
Rather

than using time and memory to convert all of the MSIL in a
portable executable (PE) file to native code. It converts
the MSIL

as needed whilst executing, then caches the resulting
native code so its accessible for any subsequent calls

JIT
----

The Just-In-Time (JIT or JITter) compiler, converts the MSIL
(Microsoft Intermediate Language) code into the native code
(CPU

Specific code).

The .NET runtime/Common Language Runtime (CLR) ships three
different classes of JITters.

<li>Econo-JIT: This compiler converts the MSIL code
into native code without any optimizations.

<li>Standard-JIT: This compiler takes the MSIL code
and optimizes it. So this compiler requires lot of
resources like,

time to compile, larger memory footprint, etc.

<li>PreJIT: This is based on the Main JIT and it
works like the traditional compilers rather than Just-In-
Time

compilers. This compiler is used at the time of
installation.

JIT does not compiles hole code ,only the code is to be
executed is compiled