CODEWITHSUNDEEP
java
Tomas Babic
Tomas Babic

Reputation:

java 1.5 to 1.4

What is the best way to convert existing jar (without source) written in java 1.5 into java 1.4.x?

Upvotes: 6

Views: 1153

Answers (6)

Craig Angus
Craig Angus

Reputation: 23208

retrotranslator is another option similar to retroweaver

Upvotes: 3

anjanb
anjanb

Reputation: 13925

as Rodeoclown said,
1) unzip the JAR

2) use a decompiler like jad(http://www.kpdus.com/jad.html) using options like these jad -d src -f -ff -s .java -space -t4 ***.class

3) and from the generated source files, compile them using JDK 1.4's javac.

4) if the 1.4 compiler works OK, rebundle into new jar

5) if 1.4 compiler has issues, you need to use
retroweaver(http://retroweaver.sourceforge.net/index.html).
That might work in some cases BUT if the class expects changes in JVM, then you're in a tough spot. If the classes uses new threading facility, you can use the JDK 1.4 version of util.concurrent from http://g.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html.

Good Luck!

Upvotes: 0

David G
David G

Reputation: 6317

Take a look at Retroweaver. It will convert the classes or jar so that it can be run using a 1.4 JRE. Depending on the 1.5 features used, you won't need any additional retroweaver run-time.

Retroweaver uses byte code enhancement. It sounds mysterious but it works.

Upvotes: 12

Steve B.
Steve B.

Reputation: 57333

As well as decompiling, you'll likely have to refactor a few things in the source code - enums, generics (I don't think the generics will be in the decompiled code but that probably means you'll be missing some casts), boxing/unboxing, etc. etc.

Upvotes: 0

RodeoClown
RodeoClown

Reputation: 13828

My gut instinct would be to decompile the jar, then recompile as 1.4.

If there are no 1.5 specific API calls in the decompiled code, that should work fine. If there are, you will need to re-engineer those sections to work in the earlier java version.

Upvotes: 0

sblundy
sblundy

Reputation: 61434

You could decompile it, then recompile. You'll probably have to fix incompatibilities by hand. Here's a thread on java decompilers.

Upvotes: 1

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