Insert key value pair in a std::map then output in a java HashMap

JHashMap.cpp

// @author Guillaume Masse

#include "JHashMap.h"

#include <string>

using namespace std;

void JHashMap::insert( std::string key, std::string value )
{
	map.insert( pair<string,string>( key, value ) );
}

jobject JHashMap::toJObject( JNIEnv* env, jclass )
{
	jclass clazz = env->FindClass("java/util/HashMap");
	jmethodID init = env->GetMethodID(clazz, "<init>", "()V");
	jobject propertyMap = env->NewObject(clazz, init);

	jmethodID putMethod = env->GetMethodID(
		clazz, 
		"put", 
		"(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;"
	);

	for( auto it = map.begin(); it != map.end(); ++it )
	{
		jstring key = (*env).NewStringUTF( (*it).first.c_str() );
		jstring value = (*env).NewStringUTF( (*it).second.c_str() );

		(*env).CallVoidMethod(
			propertyMap, 
			putMethod,
			key,
			value
		);
	}

	return propertyMap;
}

JHashMap.h

#pragma once

// @author Guillaume Masse

#include <map>
#include <string>
#include "jni.h"

class JHashMap
{

public:
	void insert( std::string key, std::string value );
	jobject toJObject(JNIEnv *, jclass);

private:

	std::map< std::string, std::string > map;
};

Why doesn't it work for me? I got an segment fault while calling CallVoidMethod.

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00000000700bb2cd, pid=8040, tid=2920
#
# JRE version: Java(TM) SE Runtime Environment (8.0_05-b13) (build 1.8.0_05-b13)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.5-b02 mixed mode windows-amd64 compressed oops)
# Problematic frame:
# V  [jvm.dll+0x13b2cd]
#
# Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
#
# An error report file with more information is saved as:
# D:/Development/Java/voj/judger/hs_err_pid8040.log
#
# If you would like to submit a bug report, please visit:
#   http://bugreport.sun.com/bugreport/crash.jsp
#

when call map "put" method, should use "env->CallObjectMethod", not "CallVoidMethod".
it's works. thk

Can someone tell me how to call toJObject function and what should I give as "jclass" parameter? I'm clueless.

Ok, figured it out. Just removed jclass parameter :)