using java -verbose option to jar only files being loaded by the interpreter

[lbrtchx]

say you have an application that uses some libraries (but not the
whole <*>.jar); using the "java -verbose" option you could know which
files have been loaded form the used library and either created a
smaller jar with all needed classes or, provided you have the source
code:
..
1._ replicate a source branch,
..
2._ recompile the "branched" source, and
..
3._ go: jar -cvf new_smaller.jar -C <branched_source> *.class
..
this is a pretty straight forward task and I was wondering if ant has
some kind of automation to achieve exactly this
..
Thanks
lbrtchx

 

[Daniel Dyer]

say you have an application that uses some libraries (but not the
whole <*>.jar); using the "java -verbose" option you could know which
files have been loaded form the used library and either created a
smaller jar with all needed classes or, provided you have the source
code:
.
1._ replicate a source branch,
.
2._ recompile the "branched" source, and
.
3._ go: jar -cvf new_smaller.jar -C <branched_source> *.class
.
this is a pretty straight forward task and I was wondering if ant has
some kind of automation to achieve exactly this
.

Properly configured, Proguard (http://proguard.sourceforge.net/) will do
something like this for you (among other things, primarily obfuscation).
It analyses the class files to see which library classes they depend on
and discards those that aren't used. This is probably safer because it
does not rely on you having to cover every possible execution path in
order to get a definitive list.

Dan.