Killing Java app from C

Question

Ive seen this question posted before, but never found a good answer. I am invoking a JVM from a legacy C app (via JNI_CreateJavaVM) and I want to be able to end the JVM and have the C app continue. The problem is that a call to System.exit() from inside the java app causes the entire native process (not just the JVM) to be killed. A call to DestroyJavaVM() does not unload the
JVM (as it claims it does in the API documentation).
Currently, the Java code calls dispose and System.gc (for good measure) on exiting, although this doesnt completely kill the java app. If the user wishes to invoke another Java app, the C code uses JNI_GetCreatedVMs to see if one already exists, and if so uses AttachThread (or GetEnv) to hook to the existing JVM to run the new Java app. The problem with this is with complicated GUI apps, the machine soon hits a wall, I guess because of un-gc'd stuff laying around.
Is there a way to kill the app from java without using System.exit or is there a way to unload the JVM from the C app?

Answer 1

Unfortunately I am running into the same issues using JDK1.4 on Win32. Basically the call to jvm->DestroyJavaVM() is NEVER returning. This seems to mainly be a problem when you use classes which require a native class loader to load native libraries. EX: classes which use System.loadLibrary("some native library"). Has anyone found a workaround to allow us to stop the jvm from the native side when these are present?
Also if anyone in interested - this is the exact c++ code I am currently using:
    if(vm != NULL) {
         * Detach the current thread from the vm so that it appears to have
         * exited when the process has detatched from the dll.
        if (vm->DetachCurrentThread() != 0) {
            MessageBox(NULL,"Could not detatch the Java Virtual Machine","DEBUG Info",MB_OK+MB_ICONEXCLAMATION);
        MessageBox(NULL,"Try to destroy the VM","DEBUG Info",MB_OK+MB_ICONEXCLAMATION);
        vm->DestroyJavaVM();
        vm = NULL;
    MessageBox(NULL,"JVM destroyed successfully","DEBUG Info",MB_OK+MB_ICONEXCLAMATION);Basically all the calls succeed except the vm->DestroyJavaVM(); including the call to detatch the current thread from the VM! Am I missing something obvious? Is this a known bug? Anyone know any workarounds? Aany and all constructive comments are welcome.