Android application crash at startup when calling native function in activity onResume

No implementation found for void qtTest.Natives.testNative() (tried Java_qtTest_Natives_testNative and Java_qtTest_Natives_testNative__)
E AndroidRuntime: FATAL EXCEPTION: main
E AndroidRuntime: Process: org.qtproject.example, PID: 9997
E AndroidRuntime: java.lang.UnsatisfiedLinkError: No implementation found for void qtTest.Natives.testNative() (tried Java_qtTest_Natives_testNative and Java_qtTest_Natives_testNative__)
E AndroidRuntime: at qtTest.Natives.testNative(Native Method)

Natives.testNative();

// now load the application library so it's accessible from this class loader
 if (libName != null)
 System.loadLibrary(libName);