Android: Purchasing crashes at startup

F ample.qthangma: java_vm_ext.cc:542] JNI DETECTED ERROR IN APPLICATION: JNI RegisterNatives called with pending exception java.lang.ClassNotFoundException: Didn't find class "org.qtproject.qt5.android.purchasing.QtInAppPurchase" on path: DexPathList[[directory "."],nativeLibraryDirectories=[/system/lib, /system/lib]]
F ample.qthangma: java_vm_ext.cc:542]   at java.lang.Class dalvik.system.BaseDexClassLoader.findClass(java.lang.String) (BaseDexClassLoader.java:134)
F ample.qthangma: java_vm_ext.cc:542]   at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String, boolean) (ClassLoader.java:379)
F ample.qthangma: java_vm_ext.cc:542]   at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String) (ClassLoader.java:312)
F ample.qthangma: java_vm_ext.cc:542]
F ample.qthangma: java_vm_ext.cc:542]     in call to RegisterNatives
F ample.qthangma: java_vm_ext.cc:542] "QtThread" prio=5 tid=15 Runnable
F ample.qthangma: java_vm_ext.cc:542]   | group="main" sCount=0 dsCount=0 flags=0 obj=0x12ec0018 self=0xe380c800
F ample.qthangma: java_vm_ext.cc:542]   | sysTid=5240 nice=0 cgrp=default sched=0/0 handle=0xcdeff970
F ample.qthangma: java_vm_ext.cc:542]   | state=R schedstat=( 51603668 6468143 167 ) utm=4 stm=1 core=1 HZ=100
F ample.qthangma: java_vm_ext.cc:542]   | stack=0xcd700000-0xcd702000 stackSize=8MB
F ample.qthangma: java_vm_ext.cc:542]   | held mutexes= "mutator lock"(shared held)
F ample.qthangma: java_vm_ext.cc:542]   native: #00 pc 004152f6  /system/lib/libart.so (art::DumpNativeStack(std::__1::basic_ostream<char, std::__1::char_traits<char>>&, int, BacktraceMap*, char const*, art::ArtMethod*, void*, bool)+198)
F ample.qthangma: java_vm_ext.cc:542]   native: #01 pc 0051048e  /system/lib/libart.so (art::Thread::DumpStack(std::__1::basic_ostream<char, std::__1::char_traits<char>>&, bool, BacktraceMap*, bool) const+382)
F ample.qthangma: java_vm_ext.cc:542]   native: #02 pc 0050b743  /system/lib/libart.so (art::Thread::Dump(std::__1::basic_ostream<char, std::__1::char_traits<char>>&, bool, BacktraceMap*, bool) const+83)
F ample.qthangma: java_vm_ext.cc:542]   native: #03 pc 0031a8b0  /system/lib/libart.so (art::JavaVMExt::JniAbort(char const*, char const*)+1088)
F ample.qthangma: java_vm_ext.cc:542]   native: #04 pc 0031ad21  /system/lib/libart.so (art::JavaVMExt::JniAbortV(char const*, char const*, char*)+113)
F ample.qthangma: java_vm_ext.cc:542]   native: #05 pc 000d60f7  /system/lib/libart.so (art::(anonymous namespace)::ScopedCheck::AbortF(char const*, ...)+71)
F ample.qthangma: java_vm_ext.cc:542]   native: #06 pc 000d4a5e  /system/lib/libart.so (art::(anonymous namespace)::ScopedCheck::CheckPossibleHeapValue(art::ScopedObjectAccess&, char, art::(anonymous namespace)::JniValueType)+1230)
F ample.qthangma: java_vm_ext.cc:542]   native: #07 pc 000d3bdb  /system/lib/libart.so (art::(anonymous namespace)::ScopedCheck::Check(art::ScopedObjectAccess&, bool, char const*, art::(anonymous namespace)::JniValueType*)+811)
F ample.qthangma: java_vm_ext.cc:542]   native: #08 pc 000cc4dc  /system/lib/libart.so (art::(anonymous namespace)::CheckJNI::RegisterNatives(_JNIEnv*, _jclass*, JNINativeMethod const*, int)+956)
F ample.qthangma: java_vm_ext.cc:542]   native: #09 pc 00008a80  /data/app/org.qtproject.example.qthangman-3jntXPxo4UJfv32SJGSSPw==/lib/x86/libQt5Purchasing_x86.so (JNI_OnLoad+112)
F ample.qthangma: java_vm_ext.cc:542]   (no managed stack frames)
F ample.qthangma: java_vm_ext.cc:542]