java.lang.UnsatisfiedLinkError when trying to follow an MIT example on SWIG usage of C++ callbacks

Question

I am trying to implement a simple application which enables C++ to do callbacks into Java. To this, I found some examples written many years ago by some people at MIT: https://github.com/swig/swig/tree/master/Examples/java/callback

However, when trying to run my own application, I get

Exception in thread "main" java.lang.UnsatisfiedLinkError: com.swig.demo.SwigDemo3JNI.swig_module_init()V at com.swig.demo.SwigDemo3JNI.swig_module_init(Native Method) at com.swig.demo.SwigDemo3JNI.<clinit>(SwigDemo3JNI.java:30) at com.swig.demo.Caller.<init>(Caller.java:39) at com.swig.demo.SwigTest.main(SwigTest.java:47)

Where SwigDemo3JNI is the Swig generated Java class, and SwigTest is the java class with main. Could anyone give me some insight on what I'm doing wrong?

Answer 1

You can set library path when init the app, the code below is used to do this:

String libraryPath = "c:/your/path/to/dll/lib";

System.setProperty("java.library.path", libraryPath);
Field sysPath = ClassLoader.class.getDeclaredField("sys_paths");
sysPath.setAccessible(true);
sysPath.set(null, null);
System.loadLibrary("the_dll_lib_name");

Hope this help you!