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, 41 insertions, 0 deletions

diff --git a/tests/auto/corelib/kernel/qjnienvironment/testdata/src/org/qtproject/qt/android/testdata/QtJniEnvironmentTestClass.java b/tests/auto/corelib/kernel/qjnienvironment/testdata/src/org/qtproject/qt/android/testdata/QtJniEnvironmentTestClass.java
new file mode 100644
index 0000000000..d6c5be45cb
--- /dev/null
+++ b/tests/auto/corelib/kernel/qjnienvironment/testdata/src/org/qtproject/qt/android/testdata/QtJniEnvironmentTestClass.java
@@ -0,0 +1,41 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+package org.qtproject.qt.android.testdatapackage;
+
+public class QtJniEnvironmentTestClass
+{
+    private static native void callbackFromJava(String message);
+
+    public static void appendJavaToString(String message)
+    {
+        callbackFromJava("From Java: " + message);
+    }
+
+}
+