What is JIT (Just- in-Time) Compilation?

What is JIT (Just- in-Time) Compilation?

In Java just-in-time (JIT) compiler is a program that turns Java bytecode (a program that contains instructions that must be interpreted) into instructions that can be sent directly to the processor. you have to write and compile a program only once. The Java on any platform will interpret the compiled bytecode into instructions understandable by the particular processor. However java virtual machine handles only one bytecode instruction at a time that makes execution slow. But Using the Java just-in-time compiler at the particular system platform compiles the bytecode into the particular system code. After the code has been (re-)compiled by the JIT compiler, it will usually run more quickly on the computer.

The just-in-time compiler comes with JVM and is used optionally. It compiles the bytecode into platform-specific executable code that is immediately executed. JIT compiler option should be used specially if the method executable is repeatedly reused in the code.

JIT Examples:
In Java JIT is JVM(java virtual machine)
In C# it is in dot net framework
In Android DVM(Dalvik virtual machine)

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