segmentation fault while running executable android ndk module

I have java application, where I use C++ code. All c++ code is compiled to .so file. I have to write unit tests for native part of the project. I wrote such unit test:

#include <gtest/gtest.h>
#include <gtest-all.cc>
#include <myTestedFile.h>
#include <jni.h>
#include <iostream>    

int main(int argc, char** argv)
{
  ::testing::InitGoogleTest(&argc, argv);
    RUN_ALL_TESTS();
    return 0;
}

TEST(MyTest, Test1)
{
    jclass jc;
    int k = jni_return_five((JNIEnv*)0, jc);
    ASSERT_EQ(k,5);
}

there is file myTestedFile.cpp

#include "myTestedFile.h"

JNIEXPORT jint JNICALL jni_freerdp_new(JNIEnv *env, jclass cls)
{
        jclass commonClass = env->FindClass(
"com/android/appportal/common/Myclass");
    return 5;
}

I start this test with such way

adb push libs/armeabi-v7a/myTest /data/local/tmp
adb push libs/armeabi-v7a/myLibrary.so /data/local/tmp
adb shel "LD_LIBRARY_PATH=/data/local/tmp data/local/tmp/myTest"

After this I have output

[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from MyTest
[ RUN      ] MyTest.Test1
Segmentation fault 

Test is passed succesfully, if I dont get references to java classes in the jni code. Can anyone help me with this error?