Linking .jar.so

Hi all,

I'm trying to convert .jar to .so and then linking it with a .cpp program.
Here are the steps I did.  I fail to link .o and .so ! May be you have 
an idea to solve this problem ?

Thanks,
Benjamin

 >> ERROR
$ gcj -o essai3.bin essai3.o -L . -lgcj -lstdc++ ant.jar.so 
ant-launcher.jar.so
test.o: In function `main':
test.cpp:22: undefined reference to `void 
org::apache::tools::ant::Main::main(JArray<java::lang::String*>*)'
collect2: ld returned 1 exit status

 >> STEPS
$ gcj -shared -findirect-dispatch -fjni -fPIC -Wl,-Bsymbolic 
/opt/ant/lib/ant.jar -o ant.jar.so
$ gcj -shared -findirect-dispatch -fjni -fPIC -Wl,-Bsymbolic 
/opt/ant/lib/ant-launcher.jar -o ant-launcher.jar.so
$ gcjh -v -cni -classpath 
/opt/ant/lib/ant.jar:/opt/ant/lib/ant-launcher.jar:/usr/lib/jvm/java-6-sun/jre/lib/rt.jar 
org.apache.tools.ant.Main
$ g++ -c -g -O -I. test.cpp
$ gcj -o essai3.bin essai3.o -L . -lgcj -lstdc++ ant.jar.so 
ant-launcher.jar.so

 >> Program : test.cpp
#include <gcj/cni.h>
#include <java/lang/System.h>
#include <java/io/PrintStream.h>
#include <java/lang/Throwable.h>

#include <org/apache/tools/ant/Main.h>

int main(int argc, char *argv[])
{
    using namespace java::lang;

    try
    {
         JvCreateJavaVM(NULL);
         JvAttachCurrentThread(NULL, NULL);

         String *message = JvNewStringLatin1("Hello from C++");
         JvInitClass(&System::class$);
         System::out->println(message);
       
        org::apache::tools::ant::Main::main(NULL);
         

         JvDetachCurrentThread();
    }
    catch (Throwable *t)
    {
         System::err->println(JvNewStringLatin1("Unhandled Java 
exception:"));
         t->printStackTrace();
    }
}