Fix registerNativeMethods for good

The initial implementation and the commit
c00ab6f8eaa3cdc9a29dd103c91b2eaf212cac9f was wrong:
* env->findClass() in fact returns a global reference, and in any
case we shouldn't be calling that, instead QJniObject would be
enough.
* The size param provided to env->RegisterNatives was wrong.
* A test for registerNativeMethods() is added to ensure such break
is not repeated again.

Task-number: QTBUG-89633
Change-Id: I4d3a6a9270755f465c40add25521fb750dd4de0a
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>
(cherry picked from commit deca7cd730a44988d3e15c551d9a82a5c75618e2)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/src/corelib/kernel/qjnienvironment.cpp b/src/corelib/kernel/qjnienvironment.cpp
index eea62116d6..ee57504327 100644
--- a/src/corelib/kernel/qjnienvironment.cpp
+++ b/src/corelib/kernel/qjnienvironment.cpp
@@ -222,12 +222,13 @@ JavaVM *QJniEnvironment::javaVM()
 */
 bool QJniEnvironment::registerNativeMethods(const char *className, JNINativeMethod methods[], int size)
 {
-    jclass clazz = findClass(className);
+    QJniObject classObject(className);
 
-    if (!clazz)
+    if (!classObject.isValid())
         return false;
 
-    if (d->jniEnv->RegisterNatives(clazz, methods, size / sizeof(methods[0])) < 0) {
+    jclass clazz = d->jniEnv->GetObjectClass(classObject.object());
+    if (d->jniEnv->RegisterNatives(clazz, methods, size) < 0) {
         exceptionCheckAndClear();
         d->jniEnv->DeleteLocalRef(clazz);
         return false;