victor-paltz / global-load-library Goto Github PK

(Please excuse my rather naive understanding of both Linux dynamic loading and JNI).

In my use case, I have two shared libraries, libA.so and libB.so, where the code in B calls a function defined in A, and where B contains "native" functions to be called from Java via JNI.

As per my incorrect intuition, I was expecting java.lang.System.load(libA.so) to make the symbols defined in A available to the code in B, but that wasn't the case. If I use LibraryLoaderJNI.loadLibrary(libA.so), as expected, the symbols in A are defined when being called from B.

However, if I attempt to access the functions in A directly from Java, I get an UnsatisfiedLinkError. To get around this, I found that I need to call both LibraryLoaderJNI.loadLibrary(libA.so) (to make it available to B) and then System.load(libA.so) (to make it available to Java).

Is this expected behavior? Is this a result of calling dlopen with the RTLD_LAZY flag? If so, could a this library be extended to allow one to specify if it should be LAZY or NOW?

[Note that I'm loading A and B from within a jar file, using the same NativeUtils approach that you are using to load libnativeload.so - which means, as far as I can tell, that the two "copies" of A loaded are independent - not sure if this is relevant to my success or not].

Thanks.