conversion from ‘std::wstring {aka std::basic_string

Can you please tell me what's the wrong this code and Any ideas on how to fix?

JNIEXPORT jstring JNICALL Java_COM_DEMO_TEST_SEND (JNIEnv
*env, jclass c, jstring param){
    const char* strParam = env->GetStringUTFChars(param, 0);
    UString data = s2ws(string(strParam));
    UString result = TEST::SEND(data);
    return env->NewStringUTF(ws2s(result).c_str());
}

i got following error.

error: conversion from ‘std::wstring {aka std::basic_string<wchar_t>}’ to non-scalar type ‘UString {aka std::basic_string<char>}’ requested
  UString data = s2ws(string(strParam));