QJniObject cannot find class in 6.2

Note: This ticket's content has been moved from QTBUG-84382, and it has been originally reported by aqadir.

Tring to call a function inside java file from main.cpp, which is extending org.qtproject.qt.android.bindings.QtActivity. My java file is under android/src/<package-name> folder.

In version 5.1, used to call like below:

QAndroidJniObject jClass = QAndroidJniObject("poc/dialogue/Hello", "(Landroid/app/Activity;)V",
                                                                             QtAndroid::androidActivity().object<jobject>());
jClass.callMethod<void>("showDialogue");

In preview version 6.2, trying to call like below:

QJniObject jClass = QJniObject("poc/dialogue/Hello", "(Landroid/app/Activity;)V",                                       QtAndroidPrivate::activity());

jClass.callMethod<void>("showDialogue");

It throws the below error in 6.2 but was working fine in 5.1. Can you please guide the correct way?

W System.err: java.lang.ClassNotFoundException: Didn't find class "poc.dialogue.Hello" on path: DexPathList[[],nativeLibraryDirectories=[/system/lib64, /product/lib64]]