[logback-user] Re: Using Logback on JDK1.4 possible?

Sebastien Pennec sebastien at qos.ch
Mon Jan 15 14:49:42 CET 2007

Hello Andy,

Thanks for you suggestion,

I've tried to convert the four logback jars (core, classic, access and log4j-bridge) 
today, using Retroweaver. My first test class that uses the jdk 1.4 version of 
logback seems to work pretty well.

I'll take a look at the library-check utility and run some more extended tests with 
the jdk 1.4 version of logback and let you know.



Gerweck Andy - agerwe wrote:
> Personally, I have had excellent luck using Retroweaver
> [http://retroweaver.sourceforge.net/] to back-convert my Java 5 code for
> deployment on earlier JVM runtimes. Retroweaver can handle *every*
> linguistic feature from Java 5. (Most of the linguistic changes in Java
> 5, even generics, have almost no incompatible effects on the compiled
> bytecode.) You feed it classes compiled with Java 5 and it spits out
> classes that will work on earlier JVMs. It requires only that you add a
> small JAR to your classpath.
> It also combines with the backport-util-concurrent project
> [http://dcl.mathcs.emory.edu/util/backport-util-concurrent/] to handle
> java.util.concurrent, Java 5's biggest library enhancement.
> Except where Java 5 adds new methods (e.g., String.format(...)) to old
> classes, Retroweaver can handle almost any Java 5 program. I put some
> back-compiled code through our QA department, which could find no
> performance or functionality problems.
> I *strongly* recommend you put in the slight extra effort to run
> Retroweaver's library-check utility. Point it to your JRE libraries and
> it will go through the code to ensure it doesn't try to use any methods
> or classes not available in your JRE (make sure to include the
> Retroweaver runtime JAR). This will catch those library changes I
> mentioned that Retroweaver doesn't handle--which is much better than a
> missing class or method at runtime. If you pass this test, you shouldn't
> have any problems. 
> I have no affiliation with Retroweaver, though I did submit a patch to
> the backport-util-concurrent project. I make no claims that it'll work
> for you, but I'd bet you could run through the LOGBack JAR and get it
> running on JDK 1.4. If you do, you may want to share your work. Just
> feed in the LOGBack JARs you need and use the output instead of the
> original.
> Andy Gerweck
> Software Engineer
> PS: In good conscience, I can't help but recommend you upgrade to Java 5
> or higher if at all possible. We're reaching the point where it's bad
> practice and poor style not to use Java 5's important language
> enhancements. There are also great runtime advantages, so it's not
> advisable to force a runtime upgrade where possible.
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Sébastien Pennec
sebastien at qos.ch

Logback: The reliable, generic, fast and flexible logging framework for Java.

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