Re: PHP compared to Java/J2EE

Lew <>
Wed, 14 Nov 2007 15:10:58 -0500
Daniel Dyer wrote:

On Wed, 14 Nov 2007 19:13:30 -0000, Steve <> wrote:

"Wojtek" <> wrote in message

Steve wrote :

php and java only get ONE pass at doing an optimization.

Nope. Modern Java implementations use adaptive optimization during
runtime. With traditional compiled languages, the compiler does it once.

what i'm saying is that this is not a continual process, like a gui, or
running process on a system. in the context of the web, java doesn't
get to
capitalize on more than a few adaptations given the
run-produce-output-and-done nature of a web hit. make sense?

No, because the JVM's optimisation is over the lifetime of the JVM not
the liftime of a single request. A request just invokes a method in a
pre-existing Java application. That single, long-running Java
application is the servlet container (something like Tomcat or Jetty).
The container can either run standalone and serve-up everything
(including HTML and static resources) or, more common in large systems,
it can sit behind Apache, which will serve the static content and defer
to the servlet container for dynamic content.

So the JIT compiler can (and does) use information it has gathered from
hundreds or thousands of hits over hours or days in order to optimise
the code.


Check out the white papers and articles on JVMs and how they optimize code.


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