Loading multiple instance of a

Question

Hi,
I'm trying to develop a Java application with Avetana Bluetooth. This library is a complete stack for Bluetooth in Java. The big problem is the hardware interface: Avetana can get only one instance for each java application running on it. So, if I have multiple hardware interface on my system, I must run multiple JVM with my application...
This happen because the Avetana library have a lot of static variable to hold some reference to the bluetooth hardware.
The big question is: can I make some Java code to create & run multiple instance of my Bluetotth code, so each Avetana Library is TRULY loaded in a ISOLATED context (so the static variables are independent each from others)?
I've tryed with custom classloading but nothing...
Here is the code from main() on StaticTestClassLoader (a code used for testing).
MyBT is the Bluetooth class wich load the Avetana library on hardware interface (specified by the method initStack(int hardwareInterfaceID)).
URL[] url = { new File("subdir").toURL() }; // because MyBT.class is in the "subdir" folder
URLClassLoader cl1 = new URLClassLoader(url);
URLClassLoader cl2 = new URLClassLoader(url);
URLClassLoader cl3 = new URLClassLoader(url);
Class<MyBT> c1 = (Class<Dummy>)cl1.loadClass("MyBT");
Class<MyBT> c2 = (Class<Dummy>)cl2.loadClass("MyBT");
Class<MyBT> c3 = (Class<Dummy>)cl3.loadClass("MyBT");
Object bt1 = c1.newInstance(); // this is line 22 where exception rise up
Object bt2 = c2.newInstance();
Object bt3 = c3.newInstance();
((MyBT)bt1).initStack(0); // run my Bluetooth application on hardware interface #1
((MyBT)bt1).initStack(1); // the same but on hardware interface #2
((MyBT)bt1).initStack(2); // the same but on hardware interface #3No error while compiling, but when running:
Exception in thread "main" java.lang.NoClassDefFoundError: MyBT
        at StaticTestClassLoader.main(StaticTestClassLoader.java:22)this happen if I didn't add on classpath the MyBT class in the "subdir". If I add it, it works but all three instance are in the same context and the library doen't load the right hardware interface...
If I omit the obejct assignement with bt1, bt2 and bt3 it works in both scenarios, but I haven't any reference to the new instantiated classes ...(so I can't call methods on there!)
Any idea, web link or suggestion?
Thanks in advance, best regards,
Francesco Pessina.

Answer 1

I think the question is detalied in an unclear manner. The substance of my question is:
- I have some code in a library with static variables.
- if I load (instantiate) this library one, twice or more, this static variables have all the same value because are static and live in the same JVM/context
- the need is to load & use this library multiple time (two or more "instance" of it) from the same application in a single JVM.
So my trouble is to write some Java code that create a runtime different context spaces in the (single) JVM so I can run this "static" library more times (one library for each context).
I've tryed with classloader and singleton but all instantiated class have always the same context, so the library have (in all the created instance) always the same static variable values.
Sorry for my english, have a good new year!
Regards,
Francesco.