I’m pretty sure the classpath and the shared library search path have little to do with each other. According to The JNI Book (which admittedly is old), on Windows if you do not use the
java.library.path system property, the DLL needs to be in the current working directory or in a directory listed in the Windows
PATH environment variable.
Looks like Oracle has removed the PDF from its website. I’ve updated the link above to point to an instance of the PDF living at University of Texas – Arlington.
Also, you can also read Oracle’s HTML version of the JNI Specification. That lives in the Java 8 section of the Java website and so hopefully will be around for a while.
At least in Java 8 (I haven’t checked earlier versions) you can do:
java -XshowSettings:properties -version
to find the shared library search path. Look for the value of the
java.library.path property in that output.