Urgent please ! How to invoke java method with diffrent argument types?

Question

Hi,
I am new to JNI.
I had gone through documentation but it is not of much help.
Can any one help me out how to invoke the below java method,
// Java class file
public class JavaClassFile
public int myJavaMethod(String[] strArray, MyClass[] myClassArray, long time, int[] ids)
// implementation of method
return 0;
// C++ file with Invokation API and invokes the myJavaMethod Java method
int main()
jclass cls_str = env->FindClass("java/lang/String");
jclass cls_MyClass = env->FindClass("MyClass");
long myLong = 2332323232;
int intArray[] = {232, 323, 32, 77 };
jclass cls_JavaClassFile = env->FindClass("JavaClassFile");
jmethodID mid_myJavaMethod = env->GetMethodID( cls_JavaClassFile, "myJavaMethod", "([Ljava/lang/String;[LMyClass;J[I)I");
// invoking the java method
//jint returnValue = env->CallIntMethod( cls_JavaClassFile, mid_myJavaMethod, stringArray, myClassArray, myLong, intArray ); --- (1)
//jint returnValue = env->CallIntMethodA( cls_JavaClassFile, mid_myJavaMethod, ...........); --- (2)
//jint returnValue = env->CallIntMethodV( cls_JavaClassFile, mid_myJavaMethod, ...........); --- (3)
Can any one tell me what is the correct way of invoking the above Java method of (1), (2) and (3) and how ?
The statement (1) is compilable but throws error at runtime, why ?
How can I use statements (2) and (3) over here ?
Thanks for any sort help.
warm and best regards.

Answer 1

You are missing some steps.
When you invoke a java method from C++, the parameters have to be java parameters, no C++ parameters.
For example, your code appears to me as thogh it is trying to pass a (C++) array of ints into a java method. No can do.
You have to construct a java in array and fill it in with values.
Here's a code snippet:
jintArray intArray = env->NewIntArray(10); // Ten elments
There are also jni functions for getting and setting array "regions".
If you are going to really do this stuff, I suggest a resource:
essential JNI by Rob Gordon
There is a chapter devoted to arrays and strings.