From: "John W. Kennedy" <jwkenne@...>
Date: 2006-07-28T11:05:11+09:00
Subject: Re: For performance, write it in C

Chad Perrin wrote:
> The canonical example for comparison, I suppose, is the Java VM vs. the
> Perl JIT compiler.  In Java, the source is compiled to bytecode and
> stored.  In Perl, the source remains in source form, and is stored as
> ASCII (or whatever).  When execution happens with Java, the VM actually
> interprets the bytecode.  Java bytecode is compiled for a virtual
> computer system (the "virtual machine"), which then runs the code as
> though it were native binary compiled for this virtual machine.  That
> virtual machine is, from the perspective of the OS, an interpreter,
> however.  Thus, Java is generally half-compiled and half-interpreted,
> which speeds up the interpretation process.

Huh? Small-system (PDA, etc.) Java implementations may use bytecode 
interpreters, but the mainstream ones started out using JIT, and were 
later upgraded to start execution by interpreting, and then, if and when 
it observes that a given segment is being repeatedly executed, compile 
it to native code.

-- 
John W. Kennedy
"The blind rulers of Logres
Nourished the land on a fallacy of rational virtue."
   -- Charles Williams.  "Taliessin through Logres: Prelude"