How to get application context for JNI library

I am trying to use a Android Java library with Unreal JNI. Problem is that the library requires an Android application context, and I have not been able to find out how to get it in Unreal.

The GameActivitivity.java naturally has an context available, but passing that through c++ code to a library seems to either mangle the context reference so that it becomes invalid object or weak ref, or the method is not found due to false signature, I think.

Here is one trial

// Get UE4 GameActivity class 
jclass game_activity_class = FAndroidApplication::FindJavaClass("com.epicgames.ue4.GameActivity");

// Use a method inserted in UPL.xml to get the context
jmethodID getActivity = env->GetMethodID(game_activity_class, "AndroidThunkJava_GetApplicationContext", "()Ljava/lang/Object;");
jobject main_ctx = env->CallObjectMethod(game_activity_class, getActivity);

// convert to global ref
globalGameCtx = reinterpret_cast<jobject>(env->NewGlobalRef(main_ctx));

// get the library class
jclass localRef = FAndroidApplication::FindJavaClass("com/comp/prod/lib/MyLibManager");

// get the initialize(...) method from the target library
jmethodID initialize_method = env->GetStaticMethodID(localRef, "initialize", "(Landroid/content/Context;Ljava/lang/String;Ljava/lang/String;)V");

// call the initialize(...) method in the target library
env->CallStaticVoidMethod(localRef, initialize_method, globalGameCtx, "TEST", "TEST");

This results into runtime error

     : signal 6 (SIGABRT), code -6 (SI_TKILL), fault addr --------

     : Abort message: 'java_vm_ext.cc:534] JNI DETECTED ERROR IN APPLICATION: can't call java.lang.Object com.epicgames.ue4.GameActivity.AndroidThunkJava_GetApplicationContext() on instance of java.lang.Class<com.epicgames.ue4.GameActivity>'

Any ideas how to fix? Or a better way to obtain context?

FAndroidApplication::GetGameActivityThis() ?

I ended up solving this by calling java lib directly from UPL file, where you can get the context simply by

Get().getApplicationContext()

Thanks for the answer. This may work as well, but can not verify it anymore.