We have a server application written in c++ and want to expand it to jdbc. So we write a c++ class that loads the JVM and invokes java methods in the java mirror class. For example, c++ side will pass a query to java side. After execution, java side will construct an object (i.e called jResult
) to store the result data. Then c++ side reads data from jResult and store data into an c++ object(called cResult ) also through jni. The whole project works fine.

In this solution, there are one java object and one c++ object have to be constructed to store the same data. For efficiency, we try to use native methods in java side to construct cResult directly.

			

			JNIEXPORT void JNICALL Java_JDBCDataSource_setColumnValue
			

			(JNIEnv * env, jobject jDataSource, jlong cArray,jstring columnValue)
			

			{
			

			int dataLen = env->GetStringLength(value);
			

			const char * value = env->GetStringUTFChar(value,  0);
			

			Array* resultArray = (Array*)cArray;
			

			resultArray->setData(value, dataLen);  //call c++ method
			

			}
			

		

			

			while(resultSet.next())
			

			{
			

			for(int i=0; i&ltcolCount; i++)
			

			{
			

			//get the column value here
			

			setColumnValue(cArrayPt, value);
			

			}
			

			}
			

		

			

			first-chance exception in a.exe (JVM.DLL): 0xC0000005: Access Violation.
			

		

Can anyone give me some hints about this?

Thanks very much.