Find user classpath while invoking JVM

Question

Hello,
I am invoking JVM in my C+ dll that will query Oracle using java classes. VC++ 6, JDK1.4.
I set the "-Djava.class.path=.;" and it finds the my class. But the problem is, it doesnt find the Oracle classes that I have put in classpath environment variable. (from command line the program runs fine)When I copy the whole classpath from the system variable in to my program, it works fine too.
But we need to make an install and can not hard code the class path in my program. How do I get user classpath that is in a system env. variable while invoking JVM?
I am sure this question has been asked before but I couldnt find answer after a couple of hours of seraching.
Thanks a lot .
Pranav.

Answer 1

As you have found, the JVM library itself doesn't use the CLASSPATH environment variable. Your C++ code needs to read the CLASSPATH environment variable and include its contents in the "-Djava.class.path=" option that you pass to the JVM. See JDK source file java.c for an example.
However, users would probably prefer not setting CLASSPATH at all. It would be better if you could locate the Oracle classes at runtime based on something else like a registry value set by the Oracle installer, or by just being installed in a well-known location. If you bundle the Oracle classes with your app, then you have full control over where they get installed relative to your app.
-slj-