Re: libgcj problem in FindClass with shared libraries.

[Andrew Haley <aph at redhat dot com>]

abhishek desai wrote:

> I am using libgcj version 3.4.6 (I have to use this version of gcc and
> libgcj) .

Well, we can't fix it.  It is ancient history.

> I have shared libraries with precompiled java clases and am
> using JNI function call "(*env)->FindClass" to get the class. Tracing
> through the _Jv_JNI_FIndClass I found that the dynamic library gets
> loaded but the symbols are not loaded into the cache.
> 
> In the function call "jclass
> gnu::gcj::runtime::VMClassLoader::findClass (jstring name)"
> there is a call to "jboolean java::lang::Runtime::loadLibraryInternal
> (jstring lib)" . This does the loading of the library by eventually
> calling dlopen in libtdl.
> 
> After this call there is no call to access the symbol from the library
> or to load it to the cache.
> But the symbol is searched for in the cache using _Jv_FindClassInCache
> which returns NULL. Is this a bug or I am missing something ? Need
> help with getting the symbols loaded.

You need to make sure that _Jv_RegisterClasses is being called when the
shared library is loaded.  If it is, then the classes in the library will
be found; if not, then you need to find out why not.

Put a breakpoint on _Jv_RegisterClasses.  You should see it called once
at startup, again when libgcj.so is loaded, and each time a shared library
is loaded.

Andrew.