Can JNI be made to honour wildcard expansion in the classpath?
I figured out the answer by reading the hotspot source code.
Only paths passed via either CLASSPATH or -cp / -classpath are subject to wildcard expansion. These are then passed as a system property to the running JVM via -Djava.class.path.
You tell a JNI-invoked JVM about a classpath via a JVMOptions structure, which may include -Djava.class.path but -classpath will not necessarily be honoured (and in practice, isn't by the hotspot implementation). Since java.class.path is directly passed to the JVM as a system property, it doesn't get wildcard expanded and therefore wildcards won't work.
No. No, it cannot. Using JNI doesn't help.
The way you would do this is by implementing your own class loader (in Java), but that class loader would have to be in the wildcard-free CLASSPATH.
You could, of course, set the CLASSPATH to its expanded form before invoking the JVM. That would work and could be done via a shell script (no JNI needed).