What are the differences between a Just-in-Time-Compiler and an Interpreter?

Question

What are the differences between a Just-in-Time-Compiler and an Interpreter, and are there differences between the .NET and the Java JIT compiler?

Answer 1

An interpreter generates and executes machine code instructions on the fly for each instruction, regardless of whether it has previously been executed.
A JIT caches the instructions that have been previously interpreted to machine code, and reuses those native machine code instructions thus saving time & resources by not having to re-interpret statements that have already been interpreted.

Answer 2

When you compile a Microsoft.NET language, the complier generates code written in the Microsoft Intermediate Language (MSIL). MSIL is a set of instructions that can quickly be translated into native code.

A Microsoft.NET application can be run only after the MSIL code is translated into native machine code. In .NET Framework, the intermediate language is complied "just in time" (JIT) into native code when the application or component is run instead of compiling the application at development time.

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