RE: Java and CPU

This is "news" to me as well.  I assumed that while Java isn't 100%
interpreted it is still a little interpreted, ie not a fully compiled binary
object, etc.

The reason I still thought this was because I've seem complaints against
java (mostly from C programmers) because it's very easy to take the class
and decompile to get the source.  I've looked at class objects and they are
almost human readable.

What type of compiler is javac considered?  What does JIT or direct
execution comipilation do to the portability of classes?

Brad

> -----Original Message-----
> From: Larry Loen [mailto:lwloen@us.ibm.com]
> Sent: Friday, March 02, 2001 8:34 AM
> To: JAVA400-L@midrange.com
> Subject: RE: Java and CPU
> 
> 
> 
> Joe wrote:
> 
> >Java isn't eRPG, Brad.  It's an interpreted language.
> 
> This is a surprising statement.
> 
> Practically no one has been running interpreted Java for the last
> three years, minimum.  At least, not on a server.  And, not for long
> on the client.
> 
> Everyone has been doing Just In Time compiling or, on the '400,
> direct (compiled) execution.  JITs may interpret for a while during
> startup, but that all the interpretation anyone does nowadays.
> 
> Interpreted Java has become a Unicorn, and always was on iSeries.
> 
> I'm surprised how many people still think Java is largely an
> interpreted language.  Interpretation is nowadays restricted to very
> specialized situations like embedded.  And, pretty universally,
> not on our box.
> 
> Servlets can beat CGI in several circumstances, because it
> is basically firing up a waiting native thread instead of the 
> potential
> for creating a new job, creating a new activation, etc. that can
> be part and parcel of running CGI.
> 
> And, throw enough SQL DB in the mix or enough back-end RPG
> processing on the other end of a data queue or something,
> and you won't be able to tell which approach is faster,
> because the back end work will drown out the rest.
> 
> Someone had a nice COMMON presentation explaining all
> this.
> 
> Now, I'm not going to argue whether Java is faster, on average,
> than RPG.  I will tell you that when RPG is faster, it is not because
> the codegen quality is better for RPG; it has to do with how 
> RPG invokes
> OS/400 services to advantage, which it was built to do (whereas
> Java uses only very generic interfaces).
> 
> 
> 
> Larry W. Loen  -   Senior Java and AS/400 Performance Analyst
>                           Dept HP4, Rochester MN
> 
> 
> +---
> | This is the JAVA/400 Mailing List!
> | To submit a new message, send your mail to JAVA400-L@midrange.com.
> | To subscribe to this list send email to JAVA400-L-SUB@midrange.com.
> | To unsubscribe from this list send email to 
> JAVA400-L-UNSUB@midrange.com.
> | Questions should be directed to the list owner: joe@zappie.net
> +---
> 
+---
| This is the JAVA/400 Mailing List!
| To submit a new message, send your mail to JAVA400-L@midrange.com.
| To subscribe to this list send email to JAVA400-L-SUB@midrange.com.
| To unsubscribe from this list send email to JAVA400-L-UNSUB@midrange.com.
| Questions should be directed to the list owner: joe@zappie.net
+---