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From Mark Womack <wom...@adobe.com>
Subject RE: log4j 1.3 minimum JDK (was Re: [VOTE] Release log4j 1.2.12rc3)
Date Wed, 17 Aug 2005 16:56:40 GMT
Endre,

Thanks for the info.  Curt has already made some changes in this area, so
I'll see what I can build upon tonight.

-Mark

> -----Original Message-----
> From: Endre StĂžlsvik [mailto:Endre@Stolsvik.com]
> Sent: Wednesday, August 17, 2005 1:45 AM
> To: Log4J Developers List; womack@adobe.com
> Subject: RE: log4j 1.3 minimum JDK (was Re: [VOTE] Release log4j
> 1.2.12rc3)
> 
> On Tue, 16 Aug 2005, Mark Womack wrote:
> 
> | We can make it so that log4j is compatible with 1.2 and happy when it
> runs.
> | Just compile using jdk 1.2 instead of jdk 1.3 or 1.4.  I think the
> messages
> | we are seeing are related to compiling the release lib with 1.4 instead
> of
> | 1.2 (or 1.1 in the case of 1.2.12).  And they are non-fatal warnings,
> not
> | errors.  I have to imagine that compiling with jdk 1.2 (or 1.1) will
> | generate compatible byte code for that jdk.  And it appears that Ant
> will
> | support compiling with different jdk's while itself runs in jdk 1.4.
> 
> I do it every day. That is, running ant and the compile on jdk 1.5, and
> then running the code on 1.3 (not 1.2, because we haven't targetted that
> for the product in question). If you don't set the "target" flag (which
> was necessary from 1.4 or something?), the 1.3 jvm says "no way, these are
> too new class files". But with the target-stuff it works. The "classic"
> flag is out, isn't it?!
> 
> You also have to set "bootclasspath" to a jdk 1.2 rt.jar to use those
> java.-classes, and thus get errors if you use 1.3+ features of the jdk.
> 
> So, set source=1.2, target=1.2 and bootclasspath=/usr/java/jdk1.2/rt.jar,
> and the code will compile according to 1.2 rules, compile to 1.2
> classfiles, and be compiled against 1.2 runtime libraries. It will thus
> run on 1.2 JREs!
> 
> |  I don't know if there is any performance penalty for running jdk 1.2
> | byte code in 1.3/1.4.
> 
> Don't believe so, and the JIT would probably eat it up anyway. The JVM
> hasn't got any new instruction set lately (ever), so it's not like "MMX"
> og "SSE" or similar new instructions that is used in 1.5, and cannot be
> used in 1.2.


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