Call Java Method from Callback function

I am writing a JNI wrapper in c++ for a particular event driven DLL. The DLL makes a network connection to another device and then calls a callback function when events are raised on the device. The DLL has 3 basic functions: connect, disconnect, and registerEventListener. RegisterEventListener takes a function pointer which is called each time an event is raised on the device.
My wrapper DLL exposes connect and disconnect functions via JNI. I can call these functions just fine from my Java code. Now the question... How do I call a Java method from my c++ callback function? I can call a Java method using env->CallXXXMethod(...) from within a function that is accessible to Java but I don't have access to the JNI parameters in my Callback function.
So how do I call a Java method from a callback function? If this cannot be done then what is the "right way" to handle native event notification with JNI?

jschell wrote:
JNI parameters? Meaning what exactly?
General outline of a callback
1. Entry
2. Get the VM, env - there are methods for this
3. Attach the thread
4. Get a java object - how depends on what you are doing, but create it or a static reference.
5. Get the java method
6. Call the java method.That is exactly correct. The callback function is called from a separate thread so using a cached pointer to JNIEnv, obtained from the original native method, crashes the JVM. The jmethodID and jclass objects (which are needed to call the static Java method) can be cached without problem. The following is the code I used to attach the current thread and call my static method.
void MyClass::onEvent(int system_id, char* data)
     //get a pointer to the Java Environment
     JNIEnv *env;
     jvm->AttachCurrentThread((void **)&env, NULL);
     //Call the Java method with the newly aquired data
     jstring js = env->NewStringUTF(data);
     env->CallStaticVoidMethod(cls, mid, system_id, js);
}My last question is about cleanup in this function. When I use NewStringUTF to "convert" my char* to jstring do I need to do anything special to clean up or will the Java garbage collector take care of it since the jstring is being passed to a Java method?
Thanks for you help

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I have been through some forums and tutorials, but nothing helps me yet.
Here's my problem : I want to access java funtion from c function.
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Hello,
I try to call a native method from java which calls java method from the same class. Exception (noSuchMethodError) is thrown. Any ideas?
Thanx in advance !
here is the source of the native method :
JNIEXPORT jint JNICALL Java_TestDll_Proc_1Mul_1Int_1Var_1Var_1Stdcall (JNIEnv * env, jclass jcl, jint jarg1, jint jarg2) {
int arg1;
int arg2;
int arg3;
jint res;
char * ch = "test";
jfieldID fid;
jmethodID mid;
int (* procedure) (int *, int * ,int *);
int mch;
arg1 = (int )jarg1;
arg2 = (int )jarg2;
procedure = GetProcAddress(libraryHandle,"Proc_Mul_Int_Var_Var_Stdcall");
procedure(&arg1,&arg2,&arg3);
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public class TestDll {
static {
System.loadLibrary("testdllwrap");
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public native int Proc_Mul_Int_Var_Var_Stdcall(int jarg1, int jarg2);
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Something is wrong with the code you posted here.
Since your native method is not static, it should have the jobject instance as a parameter in the function prototype, not a jclass. Also, you should be calling CallObjectMethod with a jobject, not jclass.
Check out Jace at http://jace.reyelts.com/jace.
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JNIEXPORT jint JNICALL Java_TestDll_Proc_1Mul_1Int_1Var_1Var_1Stdcall
(JNIEnv * env, jobject jTestDll, jint jarg1, jint jarg2) {
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