Re: How to convert a jar into so file and use it ?

[David Michel <dmichel76@googlemail.com>]

Thanks !

But I'm a bit puzzled by this

...-L. -lhello --classpath=.:hello/Hello.jar...

 Why does it need both the libhello.so and the Hello.jar file ?

David


2009/6/10 Andrew Haley <aph@redhat.com>:
> David Michel wrote:
>>
>> I have a very simple java test code that uses a public method called
>> 'coucou' of a external jar called 'Hello.jar' which contains the
>> package 'hello' and the public class 'Hello'. Here is the test code
>> Tool.java:
>>
>> import hello.Hello;
>>
>> public class Tool
>> {
>>    public static void main(String[] args)
>>    {
>>      System.out.println("main program running");
>>      Hello.coucou();
>>    }
>> }
>>
>> which I would usually compile, with the following commands:
>>
>> $ gcj -O0 -g0  -C Tool.java --classpath=./:extern/Hello.jar
>> $ gij -cp .:extern/Hello.jar Tool
>>
>> Now if I want to compile Tool.java natively with gcj, what do I need to do ?
>>
>> I can create the shared library from the jar like this:
>> $ gcj -O0 -g0  -shared -findirect-dispatch -fjni -fPIC
>> extern/Hello.jar -o extern/Hello.jar.so
>>
>>
>> I can then compile Tool.java into Tool.o with:
>> $ gcj -O0 -g0  --classpath=./:extern/Hello.jar  -c Tool.java -o Tool.o
>>
>> (altough this is using the jar and not the so ??)
>>
>> But then, I'm stuck with creating the final executable, i.e. Tool.out
>
> You didn't provide the source code for hello.Hello.  However, I'm
> guessing it's
>
> public class Hello
> {
>  public static void coucou()
>  {
>    System.out.println("coucou");
>  }
> }
>
>
>  $ gcj -C hello/Hello.java
>  $ jar cf Hello.jar hello/Hello.class
>  $ gcj -shared hello/Hello.class -o libhello.so -fpic
>  $ gcj Tool.java -L. -lhello --classpath=.:hello/Hello.jar --main=Tool
>  $ LD_LIBRARY_PATH=. ./a.out
> main program running
> coucou
>
>
> Or, with -findirect-dispatch
>
>  $ gcj -shared hello/Hello.java -o libhello.so -fpic -findirect-dispatch
>  $ gcj Tool.java -L. -lhello --classpath=.:hello/Hello.jar --main=Tool -findirect-dispatch
>
> Andrew.
>