Android: Add private API for jni in QtCore

When interfacing with Java API's on Android we need to write code using
the Java Native Interface (JNI). Writing JNI code requires a lot of
boilerplate code to be written. This patch contains API's to minimize the
amount of work needed to write JNI code.

QJNIEnvironmentPrivate:
 On creation QJNIEnvironmentPrivate will attach the current running
 thread to the Java VM, and expose the java environment.

QJNIObjectPrivate:
 Wrapps around a Java class enabling the user to access the class from C++.

Change-Id: Ib633437ae36ff513d934292e9eeefcdd5b757d29
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>

3 files changed, 2374 insertions, 3 deletions

diff --git a/src/corelib/kernel/kernel.pri b/src/corelib/kernel/kernel.pri
index 828e517ee2..26ad9f488c 100644
--- a/src/corelib/kernel/kernel.pri
+++ b/src/corelib/kernel/kernel.pri
@@ -157,7 +157,9 @@ blackberry {
 android:!android-no-sdk {
         SOURCES += \
                    kernel/qjnionload.cpp \
-                   kernel/qjnihelpers.cpp
+                   kernel/qjnihelpers.cpp \
+                   kernel/qjni.cpp
         HEADERS += \
-                   kernel/qjnihelpers_p.h
-}
\ No newline at end of file
+                   kernel/qjnihelpers_p.h \
+                   kernel/qjni_p.h
+}
diff --git a/src/corelib/kernel/qjni.cpp b/src/corelib/kernel/qjni.cpp
new file mode 100644
index 0000000000..17678fcbba
--- /dev/null
+++ b/src/corelib/kernel/qjni.cpp
@@ -0,0 +1,2105 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qjni_p.h"
+#include "qjnihelpers_p.h"
+#include <QtCore/qthreadstorage.h>
+#include <QtCore/qhash.h>
+#include <QtCore/qstring.h>
+
+QT_BEGIN_NAMESPACE
+
+static inline QString keyBase()
+{
+    return QStringLiteral("%1%2%3");
+}
+
+static QString qt_convertJString(jstring string)
+{
+    QJNIEnvironmentPrivate env;
+    int strLength = env->GetStringLength(string);
+    QString res(strLength, Qt::Uninitialized);
+    env->GetStringRegion(string, 0, strLength, reinterpret_cast<jchar *>(res.data()));
+    return res;
+}
+
+typedef QHash<QString, jclass> JClassHash;
+Q_GLOBAL_STATIC(JClassHash, cachedClasses)
+
+static jclass getCachedClass(JNIEnv *env, const char *className)
+{
+    jclass clazz = 0;
+    QString key = QLatin1String(className);
+    QHash<QString, jclass>::iterator it = cachedClasses->find(key);
+    if (it == cachedClasses->end()) {
+        jclass c = env->FindClass(className);
+        if (env->ExceptionCheck()) {
+            c = 0;
+#ifdef QT_DEBUG
+            env->ExceptionDescribe();
+#endif // QT_DEBUG
+            env->ExceptionClear();
+        }
+        if (c)
+            clazz = static_cast<jclass>(env->NewGlobalRef(c));
+        cachedClasses->insert(key, clazz);
+    } else {
+        clazz = it.value();
+    }
+    return clazz;
+}
+
+typedef QHash<QString, jmethodID> JMethodIDHash;
+Q_GLOBAL_STATIC(JMethodIDHash, cachedMethodID)
+
+static jmethodID getCachedMethodID(JNIEnv *env,
+                                   jclass clazz,
+                                   const char *name,
+                                   const char *sig,
+                                   bool isStatic = false)
+{
+    jmethodID id = 0;
+    // TODO: We need to use something else then the ref. from clazz to avoid collisions.
+    QString key = keyBase().arg(size_t(clazz)).arg(QLatin1String(name)).arg(QLatin1String(sig));
+    QHash<QString, jmethodID>::iterator it = cachedMethodID->find(key);
+    if (it == cachedMethodID->end()) {
+        if (isStatic)
+            id = env->GetStaticMethodID(clazz, name, sig);
+        else
+            id = env->GetMethodID(clazz, name, sig);
+
+        if (env->ExceptionCheck()) {
+            id = 0;
+#ifdef QT_DEBUG
+            env->ExceptionDescribe();
+#endif // QT_DEBUG
+            env->ExceptionClear();
+        }
+
+        cachedMethodID->insert(key, id);
+    } else {
+        id = it.value();
+    }
+    return id;
+}
+
+typedef QHash<QString, jfieldID> JFieldIDHash;
+Q_GLOBAL_STATIC(JFieldIDHash, cachedFieldID)
+
+static jfieldID getCachedFieldID(JNIEnv *env,
+                                 jclass clazz,
+                                 const char *name,
+                                 const char *sig,
+                                 bool isStatic = false)
+{
+    jfieldID id = 0;
+    QString key = keyBase().arg(size_t(clazz)).arg(QLatin1String(name)).arg(QLatin1String(sig));
+    QHash<QString, jfieldID>::iterator it = cachedFieldID->find(key);
+    if (it == cachedFieldID->end()) {
+        if (isStatic)
+            id = env->GetStaticFieldID(clazz, name, sig);
+        else
+            id = env->GetFieldID(clazz, name, sig);
+
+        if (env->ExceptionCheck()) {
+            id = 0;
+#ifdef QT_DEBUG
+            env->ExceptionDescribe();
+#endif // QT_DEBUG
+            env->ExceptionClear();
+        }
+
+        cachedFieldID->insert(key, id);
+    } else {
+        id = it.value();
+    }
+    return id;
+}
+
+Q_GLOBAL_STATIC(QThreadStorage<int>, refCount)
+
+QJNIEnvironmentPrivate::QJNIEnvironmentPrivate()
+    : jniEnv(0)
+{
+    JavaVM *vm = QtAndroidPrivate::javaVM();
+    if (vm->GetEnv((void**)&jniEnv, JNI_VERSION_1_6) != JNI_EDETACHED)
+        return;
+
+    if (vm->AttachCurrentThread(&jniEnv, 0) < 0)
+        return;
+
+    if (!refCount->hasLocalData())
+        refCount->setLocalData(1);
+    else
+        refCount->setLocalData(refCount->localData() + 1);
+}
+
+JNIEnv *QJNIEnvironmentPrivate::operator->()
+{
+    return jniEnv;
+}
+
+QJNIEnvironmentPrivate::operator JNIEnv* () const
+{
+    return jniEnv;
+}
+
+QJNIEnvironmentPrivate::~QJNIEnvironmentPrivate()
+{
+    if (!jniEnv)
+        return;
+
+    const int newRef = refCount->localData() - 1;
+    refCount->setLocalData(newRef);
+
+    if (newRef == 0)
+        QtAndroidPrivate::javaVM()->DetachCurrentThread();
+
+    jniEnv = 0;
+}
+
+QJNIObjectData::QJNIObjectData()
+    : m_jobject(0),
+      m_jclass(0),
+      m_own_jclass(true)
+{
+
+}
+
+QJNIObjectData::~QJNIObjectData()
+{
+    QJNIEnvironmentPrivate env;
+    if (m_jobject)
+        env->DeleteGlobalRef(m_jobject);
+    if (m_jclass && m_own_jclass)
+        env->DeleteGlobalRef(m_jclass);
+}
+
+QJNIObjectPrivate::QJNIObjectPrivate()
+    : d(new QJNIObjectData())
+{
+
+}
+
+QJNIObjectPrivate::QJNIObjectPrivate(const char *className)
+    : d(new QJNIObjectData())
+{
+    QJNIEnvironmentPrivate env;
+    d->m_jclass = getCachedClass(env, className);
+    d->m_own_jclass = false;
+    if (d->m_jclass) {
+        // get default constructor
+        jmethodID constructorId = getCachedMethodID(env, d->m_jclass, "<init>", "()V");
+        if (constructorId) {
+            jobject obj = env->NewObject(d->m_jclass, constructorId);
+            if (obj) {
+                d->m_jobject = env->NewGlobalRef(obj);
+                env->DeleteLocalRef(obj);
+            }
+        }
+    }
+}
+
+QJNIObjectPrivate::QJNIObjectPrivate(const char *className, const char *sig, ...)
+    : d(new QJNIObjectData())
+{
+    QJNIEnvironmentPrivate env;
+    d->m_jclass = getCachedClass(env, className);
+    d->m_own_jclass = false;
+    if (d->m_jclass) {
+        jmethodID constructorId = getCachedMethodID(env, d->m_jclass, "<init>", sig);
+        if (constructorId) {
+            va_list args;
+            va_start(args, sig);
+            jobject obj = env->NewObjectV(d->m_jclass, constructorId, args);
+            va_end(args);
+            if (obj) {
+                d->m_jobject = env->NewGlobalRef(obj);
+                env->DeleteLocalRef(obj);
+            }
+        }
+    }
+}
+
+QJNIObjectPrivate::QJNIObjectPrivate(jclass clazz)
+    : d(new QJNIObjectData())
+{
+    QJNIEnvironmentPrivate env;
+    d->m_jclass = static_cast<jclass>(env->NewGlobalRef(clazz));
+    if (d->m_jclass) {
+        // get default constructor
+        jmethodID constructorId = getCachedMethodID(env, d->m_jclass, "<init>", "()V");
+        if (constructorId) {
+            jobject obj = env->NewObject(d->m_jclass, constructorId);
+            if (obj) {
+                d->m_jobject = env->NewGlobalRef(obj);
+                env->DeleteLocalRef(obj);
+            }
+        }
+    }
+}
+
+QJNIObjectPrivate::QJNIObjectPrivate(jclass clazz, const char *sig, ...)
+    : d(new QJNIObjectData())
+{
+    QJNIEnvironmentPrivate env;
+    if (clazz) {
+        d->m_jclass = static_cast<jclass>(env->NewGlobalRef(clazz));
+        if (d->m_jclass) {
+            jmethodID constructorId = getCachedMethodID(env, d->m_jclass, "<init>", sig);
+            if (constructorId) {
+                va_list args;
+                va_start(args, sig);
+                jobject obj = env->NewObjectV(d->m_jclass, constructorId, args);
+                va_end(args);
+                if (obj) {
+                    d->m_jobject = env->NewGlobalRef(obj);
+                    env->DeleteLocalRef(obj);
+                }
+            }
+        }
+    }
+}
+
+QJNIObjectPrivate::QJNIObjectPrivate(jobject obj)
+    : d(new QJNIObjectData())
+{
+    if (!obj)
+        return;
+
+    QJNIEnvironmentPrivate env;
+    d->m_jobject = env->NewGlobalRef(obj);
+    d->m_jclass = static_cast<jclass>(env->NewGlobalRef(env->GetObjectClass(d->m_jobject)));
+}
+
+template <>
+void QJNIObjectPrivate::callMethod<void>(const char *methodName, const char *sig, va_list args) const
+{
+    QJNIEnvironmentPrivate env;
+    jmethodID id = getCachedMethodID(env, d->m_jclass, methodName, sig);
+    if (id) {
+        env->CallVoidMethodV(d->m_jobject, id, args);
+    }
+}
+
+template <>
+void QJNIObjectPrivate::callMethod<void>(const char *methodName, const char *sig, ...) const
+{
+    va_list args;
+    va_start(args, sig);
+    callMethod<void>(methodName, sig, args);
+    va_end(args);
+}
+
+template <>
+jboolean QJNIObjectPrivate::callMethod<jboolean>(const char *methodName, const char *sig, va_list args) const
+{
+    QJNIEnvironmentPrivate env;
+    jboolean res = 0;
+    jmethodID id = getCachedMethodID(env, d->m_jclass, methodName, sig);
+    if (id) {
+        res = env->CallBooleanMethodV(d->m_jobject, id, args);
+    }
+    return res;
+}
+
+template <>
+jboolean QJNIObjectPrivate::callMethod<jboolean>(const char *methodName, const char *sig, ...) const
+{
+    va_list args;
+    va_start(args, sig);
+    jboolean res = callMethod<jboolean>(methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jbyte QJNIObjectPrivate::callMethod<jbyte>(const char *methodName, const char *sig, va_list args) const
+{
+    QJNIEnvironmentPrivate env;
+    jbyte res = 0;
+    jmethodID id = getCachedMethodID(env, d->m_jclass, methodName, sig);
+    if (id) {
+        res = env->CallByteMethodV(d->m_jobject, id, args);
+    }
+    return res;
+}
+
+template <>
+jbyte QJNIObjectPrivate::callMethod<jbyte>(const char *methodName, const char *sig, ...) const
+{
+    va_list args;
+    va_start(args, sig);
+    jbyte res = callMethod<jbyte>(methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jchar QJNIObjectPrivate::callMethod<jchar>(const char *methodName, const char *sig, va_list args) const
+{
+    QJNIEnvironmentPrivate env;
+    jchar res = 0;
+    jmethodID id = getCachedMethodID(env, d->m_jclass, methodName, sig);
+    if (id) {
+        res = env->CallCharMethodV(d->m_jobject, id, args);
+    }
+    return res;
+}
+
+template <>
+jchar QJNIObjectPrivate::callMethod<jchar>(const char *methodName, const char *sig, ...) const
+{
+    va_list args;
+    va_start(args, sig);
+    jchar res = callMethod<jchar>(methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jshort QJNIObjectPrivate::callMethod<jshort>(const char *methodName, const char *sig, va_list args) const
+{
+    QJNIEnvironmentPrivate env;
+    jshort res = 0;
+    jmethodID id = getCachedMethodID(env, d->m_jclass, methodName, sig);
+    if (id) {
+        res = env->CallShortMethodV(d->m_jobject, id, args);
+    }
+    return res;
+}
+
+template <>
+jshort QJNIObjectPrivate::callMethod<jshort>(const char *methodName, const char *sig, ...) const
+{
+    va_list args;
+    va_start(args, sig);
+    jshort res = callMethod<jshort>(methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jint QJNIObjectPrivate::callMethod<jint>(const char *methodName, const char *sig, va_list args) const
+{
+    QJNIEnvironmentPrivate env;
+    jint res = 0;
+    jmethodID id = getCachedMethodID(env, d->m_jclass, methodName, sig);
+    if (id) {
+        res = env->CallIntMethodV(d->m_jobject, id, args);
+    }
+    return res;
+}
+
+template <>
+jint QJNIObjectPrivate::callMethod<jint>(const char *methodName, const char *sig, ...) const
+{
+    va_list args;
+    va_start(args, sig);
+    jint res = callMethod<jint>(methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jlong QJNIObjectPrivate::callMethod<jlong>(const char *methodName, const char *sig, va_list args) const
+{
+    QJNIEnvironmentPrivate env;
+    jlong res = 0;
+    jmethodID id = getCachedMethodID(env, d->m_jclass, methodName, sig);
+    if (id) {
+        res = env->CallLongMethodV(d->m_jobject, id, args);
+    }
+    return res;
+}
+
+template <>
+jlong QJNIObjectPrivate::callMethod<jlong>(const char *methodName, const char *sig, ...) const
+{
+    va_list args;
+    va_start(args, sig);
+    jlong res = callMethod<jlong>(methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jfloat QJNIObjectPrivate::callMethod<jfloat>(const char *methodName, const char *sig, va_list args) const
+{
+    QJNIEnvironmentPrivate env;
+    jfloat res = 0.f;
+    jmethodID id = getCachedMethodID(env, d->m_jclass, methodName, sig);
+    if (id) {
+        res = env->CallFloatMethodV(d->m_jobject, id, args);
+    }
+    return res;
+}
+
+template <>
+jfloat QJNIObjectPrivate::callMethod<jfloat>(const char *methodName, const char *sig, ...) const
+{
+    va_list args;
+    va_start(args, sig);
+    jfloat res = callMethod<jfloat>(methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jdouble QJNIObjectPrivate::callMethod<jdouble>(const char *methodName, const char *sig, va_list args) const
+{
+    QJNIEnvironmentPrivate env;
+    jdouble res = 0.;
+    jmethodID id = getCachedMethodID(env, d->m_jclass, methodName, sig);
+    if (id) {
+        res = env->CallDoubleMethodV(d->m_jobject, id, args);
+    }
+    return res;
+}
+
+template <>
+jdouble QJNIObjectPrivate::callMethod<jdouble>(const char *methodName, const char *sig, ...) const
+{
+    va_list args;
+    va_start(args, sig);
+    jdouble res = callMethod<jdouble>(methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+void QJNIObjectPrivate::callMethod<void>(const char *methodName) const
+{
+    callMethod<void>(methodName, "()V");
+}
+
+template <>
+jboolean QJNIObjectPrivate::callMethod<jboolean>(const char *methodName) const
+{
+    return callMethod<jboolean>(methodName, "()Z");
+}
+
+template <>
+jbyte QJNIObjectPrivate::callMethod<jbyte>(const char *methodName) const
+{
+    return callMethod<jbyte>(methodName, "()B");
+}
+
+template <>
+jchar QJNIObjectPrivate::callMethod<jchar>(const char *methodName) const
+{
+    return callMethod<jchar>(methodName, "()C");
+}
+
+template <>
+jshort QJNIObjectPrivate::callMethod<jshort>(const char *methodName) const
+{
+    return callMethod<jshort>(methodName, "()S");
+}
+
+template <>
+jint QJNIObjectPrivate::callMethod<jint>(const char *methodName) const
+{
+    return callMethod<jint>(methodName, "()I");
+}
+
+template <>
+jlong QJNIObjectPrivate::callMethod<jlong>(const char *methodName) const
+{
+    return callMethod<jlong>(methodName, "()J");
+}
+
+template <>
+jfloat QJNIObjectPrivate::callMethod<jfloat>(const char *methodName) const
+{
+    return callMethod<jfloat>(methodName, "()F");
+}
+
+template <>
+jdouble QJNIObjectPrivate::callMethod<jdouble>(const char *methodName) const
+{
+    return callMethod<jdouble>(methodName, "()D");
+}
+
+template <>
+void QJNIObjectPrivate::callStaticMethod<void>(const char *className,
+                                               const char *methodName,
+                                               const char *sig,
+                                               va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz) {
+        jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+        if (id) {
+            env->CallStaticVoidMethodV(clazz, id, args);
+        }
+    }
+}
+
+template <>
+void QJNIObjectPrivate::callStaticMethod<void>(const char *className,
+                                               const char *methodName,
+                                               const char *sig,
+                                               ...)
+{
+    va_list args;
+    va_start(args, sig);
+    callStaticMethod<void>(className, methodName, sig, args);
+    va_end(args);
+}
+
+template <>
+void QJNIObjectPrivate::callStaticMethod<void>(jclass clazz,
+                                               const char *methodName,
+                                               const char *sig,
+                                               va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+    if (id) {
+        env->CallStaticVoidMethodV(clazz, id, args);
+    }
+}
+
+template <>
+void QJNIObjectPrivate::callStaticMethod<void>(jclass clazz,
+                                               const char *methodName,
+                                               const char *sig,
+                                               ...)
+{
+    va_list args;
+    va_start(args, sig);
+    callStaticMethod<void>(clazz, methodName, sig, args);
+    va_end(args);
+}
+
+template <>
+jboolean QJNIObjectPrivate::callStaticMethod<jboolean>(const char *className,
+                                                       const char *methodName,
+                                                       const char *sig,
+                                                       va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jboolean res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz) {
+        jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+        if (id) {
+            res = env->CallStaticBooleanMethodV(clazz, id, args);
+        }
+    }
+
+    return res;
+}
+
+template <>
+jboolean QJNIObjectPrivate::callStaticMethod<jboolean>(const char *className,
+                                                       const char *methodName,
+                                                       const char *sig,
+                                                       ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jboolean res = callStaticMethod<jboolean>(className, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jboolean QJNIObjectPrivate::callStaticMethod<jboolean>(jclass clazz,
+                                                       const char *methodName,
+                                                       const char *sig,
+                                                       va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jboolean res = 0;
+    jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+    if (id) {
+        res = env->CallStaticBooleanMethodV(clazz, id, args);
+    }
+
+    return res;
+}
+
+template <>
+jboolean QJNIObjectPrivate::callStaticMethod<jboolean>(jclass clazz,
+                                                       const char *methodName,
+                                                       const char *sig,
+                                                       ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jboolean res = callStaticMethod<jboolean>(clazz, methodName, sig);
+    va_end(args);
+    return res;
+}
+
+template <>
+jbyte QJNIObjectPrivate::callStaticMethod<jbyte>(const char *className,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jbyte res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz) {
+        jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+        if (id) {
+            res = env->CallStaticByteMethodV(clazz, id, args);
+        }
+    }
+
+    return res;
+}
+
+template <>
+jbyte QJNIObjectPrivate::callStaticMethod<jbyte>(const char *className,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jbyte res = callStaticMethod<jbyte>(className, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jbyte QJNIObjectPrivate::callStaticMethod<jbyte>(jclass clazz,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jbyte res = 0;
+    jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+    if (id) {
+        res = env->CallStaticByteMethodV(clazz, id, args);
+    }
+
+    return res;
+}
+
+template <>
+jbyte QJNIObjectPrivate::callStaticMethod<jbyte>(jclass clazz,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jbyte res = callStaticMethod<jbyte>(clazz, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jchar QJNIObjectPrivate::callStaticMethod<jchar>(const char *className,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jchar res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz) {
+        jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+        if (id) {
+            res = env->CallStaticCharMethodV(clazz, id, args);
+        }
+    }
+
+    return res;
+}
+
+template <>
+jchar QJNIObjectPrivate::callStaticMethod<jchar>(const char *className,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jchar res = callStaticMethod<jchar>(className, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jchar QJNIObjectPrivate::callStaticMethod<jchar>(jclass clazz,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jchar res = 0;
+    jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+    if (id) {
+        res = env->CallStaticCharMethodV(clazz, id, args);
+    }
+
+    return res;
+}
+
+template <>
+jchar QJNIObjectPrivate::callStaticMethod<jchar>(jclass clazz,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jchar res = callStaticMethod<jchar>(clazz, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jshort QJNIObjectPrivate::callStaticMethod<jshort>(const char *className,
+                                                   const char *methodName,
+                                                   const char *sig,
+                                                   va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jshort res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz) {
+        jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+        if (id) {
+            res = env->CallStaticShortMethodV(clazz, id, args);
+        }
+    }
+
+    return res;
+}
+
+template <>
+jshort QJNIObjectPrivate::callStaticMethod<jshort>(const char *className,
+                                                   const char *methodName,
+                                                   const char *sig,
+                                                   ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jshort res = callStaticMethod<jshort>(className, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jshort QJNIObjectPrivate::callStaticMethod<jshort>(jclass clazz,
+                                                   const char *methodName,
+                                                   const char *sig,
+                                                   va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jshort res = 0;
+    jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+    if (id) {
+        res = env->CallStaticShortMethodV(clazz, id, args);
+    }
+
+    return res;
+}
+
+template <>
+jshort QJNIObjectPrivate::callStaticMethod<jshort>(jclass clazz,
+                                                   const char *methodName,
+                                                   const char *sig,
+                                                   ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jshort res = callStaticMethod<jshort>(clazz, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jint QJNIObjectPrivate::callStaticMethod<jint>(const char *className,
+                                               const char *methodName,
+                                               const char *sig,
+                                               va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jint res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz) {
+        jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+        if (id) {
+            res = env->CallStaticIntMethodV(clazz, id, args);
+        }
+    }
+
+    return res;
+}
+
+template <>
+jint QJNIObjectPrivate::callStaticMethod<jint>(const char *className,
+                                               const char *methodName,
+                                               const char *sig,
+                                               ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jint res = callStaticMethod<jint>(className, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jint QJNIObjectPrivate::callStaticMethod<jint>(jclass clazz,
+                                               const char *methodName,
+                                               const char *sig,
+                                               va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jint res = 0;
+    jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+    if (id) {
+        res = env->CallStaticIntMethodV(clazz, id, args);
+    }
+
+    return res;
+}
+
+template <>
+jint QJNIObjectPrivate::callStaticMethod<jint>(jclass clazz,
+                                               const char *methodName,
+                                               const char *sig,
+                                               ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jint res = callStaticMethod<jint>(clazz, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jlong QJNIObjectPrivate::callStaticMethod<jlong>(const char *className,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jlong res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz) {
+        jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+        if (id) {
+            res = env->CallStaticLongMethodV(clazz, id, args);
+        }
+    }
+
+    return res;
+}
+
+template <>
+jlong QJNIObjectPrivate::callStaticMethod<jlong>(const char *className,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jlong res = callStaticMethod<jlong>(className, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jlong QJNIObjectPrivate::callStaticMethod<jlong>(jclass clazz,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jlong res = 0;
+    jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+    if (id) {
+        res = env->CallStaticLongMethodV(clazz, id, args);
+    }
+
+    return res;
+}
+
+template <>
+jlong QJNIObjectPrivate::callStaticMethod<jlong>(jclass clazz,
+                                                 const char *methodName,
+                                                 const char *sig,
+                                                 ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jlong res = callStaticMethod<jlong>(clazz, methodName, sig);
+    va_end(args);
+    return res;
+}
+
+template <>
+jfloat QJNIObjectPrivate::callStaticMethod<jfloat>(const char *className,
+                                                   const char *methodName,
+                                                   const char *sig,
+                                                   va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jfloat res = 0.f;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz) {
+        jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+        if (id) {
+            res = env->CallStaticFloatMethodV(clazz, id, args);
+        }
+    }
+
+    return res;
+}
+
+template <>
+jfloat QJNIObjectPrivate::callStaticMethod<jfloat>(const char *className,
+                                                   const char *methodName,
+                                                   const char *sig,
+                                                   ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jfloat res = callStaticMethod<jfloat>(className, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jfloat QJNIObjectPrivate::callStaticMethod<jfloat>(jclass clazz,
+                                                   const char *methodName,
+                                                   const char *sig,
+                                                   va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jfloat res = 0.f;
+    jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+    if (id) {
+        res = env->CallStaticFloatMethodV(clazz, id, args);
+    }
+
+    return res;
+}
+
+template <>
+jfloat QJNIObjectPrivate::callStaticMethod<jfloat>(jclass clazz,
+                                                   const char *methodName,
+                                                   const char *sig,
+                                                   ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jfloat res = callStaticMethod<jfloat>(clazz, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jdouble QJNIObjectPrivate::callStaticMethod<jdouble>(const char *className,
+                                                     const char *methodName,
+                                                     const char *sig,
+                                                     va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jdouble res = 0.;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz) {
+        jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+        if (id) {
+            res = env->CallStaticDoubleMethodV(clazz, id, args);
+        }
+    }
+
+    return res;
+}
+
+template <>
+jdouble QJNIObjectPrivate::callStaticMethod<jdouble>(const char *className,
+                                                     const char *methodName,
+                                                     const char *sig,
+                                                     ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jdouble res = callStaticMethod<jdouble>(className, methodName, sig);
+    va_end(args);
+    return res;
+}
+
+template <>
+jdouble QJNIObjectPrivate::callStaticMethod<jdouble>(jclass clazz,
+                                                     const char *methodName,
+                                                     const char *sig,
+                                                     va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jdouble res = 0.;
+    jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+    if (id) {
+        res = env->CallStaticDoubleMethodV(clazz, id, args);
+    }
+
+    return res;
+}
+
+template <>
+jdouble QJNIObjectPrivate::callStaticMethod<jdouble>(jclass clazz,
+                                                     const char *methodName,
+                                                     const char *sig,
+                                                     ...)
+{
+    va_list args;
+    va_start(args, sig);
+    jdouble res = callStaticMethod<jdouble>(clazz, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+void QJNIObjectPrivate::callStaticMethod<void>(const char *className, const char *methodName)
+{
+    callStaticMethod<void>(className, methodName, "()V");
+}
+
+template <>
+void QJNIObjectPrivate::callStaticMethod<void>(jclass clazz, const char *methodName)
+{
+    callStaticMethod<void>(clazz, methodName, "()V");
+}
+
+template <>
+jboolean QJNIObjectPrivate::callStaticMethod<jboolean>(const char *className, const char *methodName)
+{
+    return callStaticMethod<jboolean>(className, methodName, "()Z");
+}
+
+template <>
+jboolean QJNIObjectPrivate::callStaticMethod<jboolean>(jclass clazz, const char *methodName)
+{
+    return callStaticMethod<jboolean>(clazz, methodName, "()Z");
+}
+
+template <>
+jbyte QJNIObjectPrivate::callStaticMethod<jbyte>(const char *className, const char *methodName)
+{
+    return callStaticMethod<jbyte>(className, methodName, "()B");
+}
+
+template <>
+jbyte QJNIObjectPrivate::callStaticMethod<jbyte>(jclass clazz, const char *methodName)
+{
+    return callStaticMethod<jbyte>(clazz, methodName, "()B");
+}
+
+template <>
+jchar QJNIObjectPrivate::callStaticMethod<jchar>(const char *className, const char *methodName)
+{
+    return callStaticMethod<jchar>(className, methodName, "()C");
+}
+
+template <>
+jchar QJNIObjectPrivate::callStaticMethod<jchar>(jclass clazz, const char *methodName)
+{
+    return callStaticMethod<jchar>(clazz, methodName, "()C");
+}
+
+template <>
+jshort QJNIObjectPrivate::callStaticMethod<jshort>(const char *className, const char *methodName)
+{
+    return callStaticMethod<jshort>(className, methodName, "()S");
+}
+
+template <>
+jshort QJNIObjectPrivate::callStaticMethod<jshort>(jclass clazz, const char *methodName)
+{
+    return callStaticMethod<jshort>(clazz, methodName, "()S");
+}
+
+template <>
+jint QJNIObjectPrivate::callStaticMethod<jint>(const char *className, const char *methodName)
+{
+    return callStaticMethod<jint>(className, methodName, "()I");
+}
+
+template <>
+jint QJNIObjectPrivate::callStaticMethod<jint>(jclass clazz, const char *methodName)
+{
+    return callStaticMethod<jint>(clazz, methodName, "()I");
+}
+
+template <>
+jlong QJNIObjectPrivate::callStaticMethod<jlong>(const char *className, const char *methodName)
+{
+    return callStaticMethod<jlong>(className, methodName, "()J");
+}
+
+template <>
+jlong QJNIObjectPrivate::callStaticMethod<jlong>(jclass clazz, const char *methodName)
+{
+    return callStaticMethod<jlong>(clazz, methodName, "()J");
+}
+
+template <>
+jfloat QJNIObjectPrivate::callStaticMethod<jfloat>(const char *className, const char *methodName)
+{
+    return callStaticMethod<jfloat>(className, methodName, "()F");
+}
+
+template <>
+jfloat QJNIObjectPrivate::callStaticMethod<jfloat>(jclass clazz, const char *methodName)
+{
+    return callStaticMethod<jfloat>(clazz, methodName, "()F");
+}
+
+template <>
+jdouble QJNIObjectPrivate::callStaticMethod<jdouble>(const char *className, const char *methodName)
+{
+    return callStaticMethod<jdouble>(className, methodName, "()D");
+}
+
+template <>
+jdouble QJNIObjectPrivate::callStaticMethod<jdouble>(jclass clazz, const char *methodName)
+{
+    return callStaticMethod<jdouble>(clazz, methodName, "()D");
+}
+
+QJNIObjectPrivate QJNIObjectPrivate::callObjectMethod(const char *methodName,
+                                                      const char *sig,
+                                                      va_list args) const
+{
+    QJNIEnvironmentPrivate env;
+    jobject res = 0;
+    jmethodID id = getCachedMethodID(env, d->m_jclass, methodName, sig);
+    if (id) {
+        res = env->CallObjectMethodV(d->m_jobject, id, args);
+    }
+    return res;
+}
+
+QJNIObjectPrivate QJNIObjectPrivate::callObjectMethod(const char *methodName,
+                                                      const char *sig,
+                                                      ...) const
+{
+    va_list args;
+    va_start(args, sig);
+    QJNIObjectPrivate res = callObjectMethod(methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+QJNIObjectPrivate QJNIObjectPrivate::callObjectMethod<jstring>(const char *methodName) const
+{
+    return callObjectMethod(methodName, "()Ljava/lang/String;");
+}
+
+template <>
+QJNIObjectPrivate QJNIObjectPrivate::callObjectMethod<jbooleanArray>(const char *methodName) const
+{
+    return callObjectMethod(methodName, "()[Z");
+}
+
+template <>
+QJNIObjectPrivate QJNIObjectPrivate::callObjectMethod<jbyteArray>(const char *methodName) const
+{
+    return callObjectMethod(methodName, "()[B");
+}
+
+template <>
+QJNIObjectPrivate QJNIObjectPrivate::callObjectMethod<jshortArray>(const char *methodName) const
+{
+    return callObjectMethod(methodName, "()[S");
+}
+
+template <>
+QJNIObjectPrivate QJNIObjectPrivate::callObjectMethod<jintArray>(const char *methodName) const
+{
+    return callObjectMethod(methodName, "()[I");
+}
+
+template <>
+QJNIObjectPrivate QJNIObjectPrivate::callObjectMethod<jlongArray>(const char *methodName) const
+{
+    return callObjectMethod(methodName, "()[J");
+}
+
+template <>
+QJNIObjectPrivate QJNIObjectPrivate::callObjectMethod<jfloatArray>(const char *methodName) const
+{
+    return callObjectMethod(methodName, "()[F");
+}
+
+template <>
+QJNIObjectPrivate QJNIObjectPrivate::callObjectMethod<jdoubleArray>(const char *methodName) const
+{
+    return callObjectMethod(methodName, "()[D");
+}
+
+QJNIObjectPrivate QJNIObjectPrivate::callStaticObjectMethod(const char *className,
+                                                            const char *methodName,
+                                                            const char *sig,
+                                                            va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jobject res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz) {
+        jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+        if (id) {
+            res = env->CallStaticObjectMethodV(clazz, id, args);
+        }
+    }
+
+    return res;
+}
+
+QJNIObjectPrivate QJNIObjectPrivate::callStaticObjectMethod(const char *className,
+                                                            const char *methodName,
+                                                            const char *sig,
+                                                            ...)
+{
+    va_list args;
+    va_start(args, sig);
+    QJNIObjectPrivate res = callStaticObjectMethod(className, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+QJNIObjectPrivate QJNIObjectPrivate::callStaticObjectMethod(jclass clazz,
+                                                            const char *methodName,
+                                                            const char *sig,
+                                                            va_list args)
+{
+    QJNIEnvironmentPrivate env;
+    jobject res = 0;
+    jmethodID id = getCachedMethodID(env, clazz, methodName, sig, true);
+    if (id) {
+        res = env->CallStaticObjectMethodV(clazz, id, args);
+    }
+
+    return res;
+}
+
+QJNIObjectPrivate QJNIObjectPrivate::callStaticObjectMethod(jclass clazz,
+                                                            const char *methodName,
+                                                            const char *sig,
+                                                            ...)
+{
+    va_list args;
+    va_start(args, sig);
+    QJNIObjectPrivate res = callStaticObjectMethod(clazz, methodName, sig, args);
+    va_end(args);
+    return res;
+}
+
+template <>
+jboolean QJNIObjectPrivate::getField<jboolean>(const char *fieldName) const
+{
+    QJNIEnvironmentPrivate env;
+    jboolean res = 0;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "Z");
+    if (id)
+        res = env->GetBooleanField(d->m_jobject, id);
+
+    return res;
+}
+
+template <>
+jbyte QJNIObjectPrivate::getField<jbyte>(const char *fieldName) const
+{
+    QJNIEnvironmentPrivate env;
+    jbyte res = 0;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "B");
+    if (id)
+        res = env->GetByteField(d->m_jobject, id);
+
+    return res;
+}
+
+template <>
+jchar QJNIObjectPrivate::getField<jchar>(const char *fieldName) const
+{
+    QJNIEnvironmentPrivate env;
+    jchar res = 0;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "C");
+    if (id)
+        res = env->GetCharField(d->m_jobject, id);
+
+    return res;
+}
+
+template <>
+jshort QJNIObjectPrivate::getField<jshort>(const char *fieldName) const
+{
+    QJNIEnvironmentPrivate env;
+    jshort res = 0;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "S");
+    if (id)
+        res = env->GetShortField(d->m_jobject, id);
+
+    return res;
+}
+
+template <>
+jint QJNIObjectPrivate::getField<jint>(const char *fieldName) const
+{
+    QJNIEnvironmentPrivate env;
+    jint res = 0;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "I");
+    if (id)
+        res = env->GetIntField(d->m_jobject, id);
+
+    return res;
+}
+
+template <>
+jlong QJNIObjectPrivate::getField<jlong>(const char *fieldName) const
+{
+    QJNIEnvironmentPrivate env;
+    jlong res = 0;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "J");
+    if (id)
+        res = env->GetLongField(d->m_jobject, id);
+
+    return res;
+}
+
+template <>
+jfloat QJNIObjectPrivate::getField<jfloat>(const char *fieldName) const
+{
+    QJNIEnvironmentPrivate env;
+    jfloat res = 0.f;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "F");
+    if (id)
+        res = env->GetFloatField(d->m_jobject, id);
+
+    return res;
+}
+
+template <>
+jdouble QJNIObjectPrivate::getField<jdouble>(const char *fieldName) const
+{
+    QJNIEnvironmentPrivate env;
+    jdouble res = 0.;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "D");
+    if (id)
+        res = env->GetDoubleField(d->m_jobject, id);
+
+    return res;
+}
+
+template <>
+jboolean QJNIObjectPrivate::getStaticField<jboolean>(jclass clazz, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jboolean res = 0;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "Z", true);
+    if (id)
+        res = env->GetStaticBooleanField(clazz, id);
+
+    return res;
+}
+
+template <>
+jboolean QJNIObjectPrivate::getStaticField<jboolean>(const char *className, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jboolean res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        res = getStaticField<jboolean>(clazz, fieldName);
+
+    return res;
+}
+
+template <>
+jbyte QJNIObjectPrivate::getStaticField<jbyte>(jclass clazz, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jbyte res = 0;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "B", true);
+    if (id)
+        res = env->GetStaticByteField(clazz, id);
+
+    return res;
+}
+
+template <>
+jbyte QJNIObjectPrivate::getStaticField<jbyte>(const char *className, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jbyte res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        res = getStaticField<jbyte>(clazz, fieldName);
+
+    return res;
+}
+
+template <>
+jchar QJNIObjectPrivate::getStaticField<jchar>(jclass clazz, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jchar res = 0;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "C", true);
+    if (id)
+        res = env->GetStaticCharField(clazz, id);
+
+    return res;
+}
+
+template <>
+jchar QJNIObjectPrivate::getStaticField<jchar>(const char *className, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jchar res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        res = getStaticField<jchar>(clazz, fieldName);
+
+    return res;
+}
+
+template <>
+jshort QJNIObjectPrivate::getStaticField<jshort>(jclass clazz, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jshort res = 0;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "S", true);
+    if (id)
+        res = env->GetStaticShortField(clazz, id);
+
+    return res;
+}
+
+template <>
+jshort QJNIObjectPrivate::getStaticField<jshort>(const char *className, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jshort res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        res = getStaticField<jshort>(clazz, fieldName);
+
+    return res;
+}
+
+template <>
+jint QJNIObjectPrivate::getStaticField<jint>(jclass clazz, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jint res = 0;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "I", true);
+    if (id)
+        res = env->GetStaticIntField(clazz, id);
+
+    return res;
+}
+
+template <>
+jint QJNIObjectPrivate::getStaticField<jint>(const char *className, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jint res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        res = getStaticField<jint>(clazz, fieldName);
+
+    return res;
+}
+
+template <>
+jlong QJNIObjectPrivate::getStaticField<jlong>(jclass clazz, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jlong res = 0;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "J", true);
+    if (id)
+        res = env->GetStaticLongField(clazz, id);
+
+    return res;
+}
+
+template <>
+jlong QJNIObjectPrivate::getStaticField<jlong>(const char *className, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jlong res = 0;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        res = getStaticField<jlong>(clazz, fieldName);
+
+    return res;
+}
+
+template <>
+jfloat QJNIObjectPrivate::getStaticField<jfloat>(jclass clazz, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jfloat res = 0.f;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "F", true);
+    if (id)
+        res = env->GetStaticFloatField(clazz, id);
+
+    return res;
+}
+
+template <>
+jfloat QJNIObjectPrivate::getStaticField<jfloat>(const char *className, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jfloat res = 0.f;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        res = getStaticField<jfloat>(clazz, fieldName);
+
+    return res;
+}
+
+template <>
+jdouble QJNIObjectPrivate::getStaticField<jdouble>(jclass clazz, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jdouble res = 0.;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "D", true);
+    if (id)
+        res = env->GetStaticDoubleField(clazz, id);
+
+    return res;
+}
+
+template <>
+jdouble QJNIObjectPrivate::getStaticField<jdouble>(const char *className, const char *fieldName)
+{
+    QJNIEnvironmentPrivate env;
+    jdouble res = 0.;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        res = getStaticField<jdouble>(clazz, fieldName);
+
+    return res;
+}
+
+QJNIObjectPrivate QJNIObjectPrivate::getObjectField(const char *fieldName,
+                                                    const char *sig) const
+{
+    QJNIEnvironmentPrivate env;
+    jobject res = 0;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, sig);
+    if (id)
+        res = env->GetObjectField(d->m_jobject, id);
+
+    return res;
+}
+
+QJNIObjectPrivate QJNIObjectPrivate::getStaticObjectField(const char *className,
+                                                          const char *fieldName,
+                                                          const char *sig)
+{
+    QJNIEnvironmentPrivate env;
+    QJNIObjectPrivate res;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        res = getStaticObjectField(clazz, fieldName, sig);
+
+    return res;
+}
+
+QJNIObjectPrivate QJNIObjectPrivate::getStaticObjectField(jclass clazz,
+                                                          const char *fieldName,
+                                                          const char *sig)
+{
+    QJNIEnvironmentPrivate env;
+    jobject res = 0;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, sig, true);
+    if (id)
+        res = env->GetStaticObjectField(clazz, id);
+
+    return res;
+}
+
+template <>
+void QJNIObjectPrivate::setField<jboolean>(const char *fieldName, jboolean value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "Z");
+    if (id)
+        env->SetBooleanField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jbyte>(const char *fieldName, jbyte value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "B");
+    if (id)
+        env->SetByteField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jchar>(const char *fieldName, jchar value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "C");
+    if (id)
+        env->SetCharField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jshort>(const char *fieldName, jshort value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "S");
+    if (id)
+        env->SetShortField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jint>(const char *fieldName, jint value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "I");
+    if (id)
+        env->SetIntField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jlong>(const char *fieldName, jlong value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "J");
+    if (id)
+        env->SetLongField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jfloat>(const char *fieldName, jfloat value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "F");
+    if (id)
+        env->SetFloatField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jdouble>(const char *fieldName, jdouble value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "D");
+    if (id)
+        env->SetDoubleField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jbooleanArray>(const char *fieldName, jbooleanArray value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "[Z");
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jbyteArray>(const char *fieldName, jbyteArray value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "[B");
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jcharArray>(const char *fieldName, jcharArray value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "[C");
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jshortArray>(const char *fieldName, jshortArray value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "[S");
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jintArray>(const char *fieldName, jintArray value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "[I");
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jlongArray>(const char *fieldName, jlongArray value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "[J");
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jfloatArray>(const char *fieldName, jfloatArray value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "[F");
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jdoubleArray>(const char *fieldName, jdoubleArray value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "[D");
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jstring>(const char *fieldName, jstring value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, "Ljava/lang/String;");
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jobject>(const char *fieldName,
+                                          const char *sig,
+                                          jobject value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, sig);
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setField<jobjectArray>(const char *fieldName,
+                                               const char *sig,
+                                               jobjectArray value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, d->m_jclass, fieldName, sig);
+    if (id)
+        env->SetObjectField(d->m_jobject, id, value);
+
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jboolean>(jclass clazz,
+                                                 const char *fieldName,
+                                                 jboolean value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "Z", true);
+    if (id)
+        env->SetStaticBooleanField(clazz, id, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jboolean>(const char *className,
+                                                 const char *fieldName,
+                                                 jboolean value)
+{
+    QJNIEnvironmentPrivate env;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        setStaticField<jboolean>(clazz, fieldName, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jbyte>(jclass clazz,
+                                              const char *fieldName,
+                                              jbyte value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "B", true);
+    if (id)
+        env->SetStaticByteField(clazz, id, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jbyte>(const char *className,
+                                              const char *fieldName,
+                                              jbyte value)
+{
+    QJNIEnvironmentPrivate env;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        setStaticField<jbyte>(clazz, fieldName, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jchar>(jclass clazz,
+                                              const char *fieldName,
+                                              jchar value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "C", true);
+    if (id)
+        env->SetStaticCharField(clazz, id, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jchar>(const char *className,
+                                              const char *fieldName,
+                                              jchar value)
+{
+    QJNIEnvironmentPrivate env;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        setStaticField<jchar>(clazz, fieldName, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jshort>(jclass clazz,
+                                               const char *fieldName,
+                                               jshort value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "S", true);
+    if (id)
+        env->SetStaticShortField(clazz, id, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jshort>(const char *className,
+                                               const char *fieldName,
+                                               jshort value)
+{
+    QJNIEnvironmentPrivate env;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        setStaticField<jshort>(clazz, fieldName, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jint>(jclass clazz,
+                                             const char *fieldName,
+                                             jint value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "I", true);
+    if (id)
+        env->SetStaticIntField(clazz, id, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jint>(const char *className,
+                                             const char *fieldName,
+                                             jint value)
+{
+    QJNIEnvironmentPrivate env;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        setStaticField<jint>(clazz, fieldName, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jlong>(jclass clazz,
+                                              const char *fieldName,
+                                              jlong value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "J", true);
+    if (id)
+        env->SetStaticLongField(clazz, id, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jlong>(const char *className,
+                                              const char *fieldName,
+                                              jlong value)
+{
+    QJNIEnvironmentPrivate env;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        setStaticField<jlong>(clazz, fieldName, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jfloat>(jclass clazz,
+                                               const char *fieldName,
+                                               jfloat value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "F", true);
+    if (id)
+        env->SetStaticFloatField(clazz, id, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jfloat>(const char *className,
+                                               const char *fieldName,
+                                               jfloat value)
+{
+    QJNIEnvironmentPrivate env;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        setStaticField<jfloat>(clazz, fieldName, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jdouble>(jclass clazz,
+                                                const char *fieldName,
+                                                jdouble value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, "D", true);
+    if (id)
+        env->SetStaticDoubleField(clazz, id, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jdouble>(const char *className,
+                                                const char *fieldName,
+                                                jdouble value)
+{
+    QJNIEnvironmentPrivate env;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        setStaticField<jdouble>(clazz, fieldName, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jobject>(jclass clazz,
+                                                const char *fieldName,
+                                                const char *sig,
+                                                jobject value)
+{
+    QJNIEnvironmentPrivate env;
+    jfieldID id = getCachedFieldID(env, clazz, fieldName, sig, true);
+    if (id)
+        env->SetStaticObjectField(clazz, id, value);
+}
+
+template <>
+void QJNIObjectPrivate::setStaticField<jobject>(const char *className,
+                                                const char *fieldName,
+                                                const char *sig,
+                                                jobject value)
+{
+    QJNIEnvironmentPrivate env;
+    jclass clazz = getCachedClass(env, className);
+    if (clazz)
+        setStaticField<jobject>(clazz, fieldName, sig, value);
+}
+
+QJNIObjectPrivate QJNIObjectPrivate::fromString(const QString &string)
+{
+    QJNIEnvironmentPrivate env;
+    jstring res = env->NewString(reinterpret_cast<const jchar*>(string.constData()),
+                                        string.length());
+    return res;
+}
+
+QString QJNIObjectPrivate::toString() const
+{
+    if (!isValid())
+        return QString();
+
+    QJNIObjectPrivate string = callObjectMethod<jstring>("toString");
+    return qt_convertJString(static_cast<jstring>(string.object()));
+}
+
+bool QJNIObjectPrivate::isClassAvailable(const char *className)
+{
+    QJNIEnvironmentPrivate env;
+
+    if (!env)
+        return false;
+
+    jclass clazz = getCachedClass(env, className);
+    return (clazz != 0);
+}
+
+bool QJNIObjectPrivate::isValid() const
+{
+    return d->m_jobject;
+}
+
+bool QJNIObjectPrivate::isSameObject(jobject obj) const
+{
+    QJNIEnvironmentPrivate env;
+    return env->IsSameObject(d->m_jobject, obj);
+}
+
+bool QJNIObjectPrivate::isSameObject(const QJNIObjectPrivate &other) const
+{
+    return isSameObject(other.d->m_jobject);
+}
+
+QT_END_NAMESPACE
+
diff --git a/src/corelib/kernel/qjni_p.h b/src/corelib/kernel/qjni_p.h
new file mode 100644
index 0000000000..912b5dbee4
--- /dev/null
+++ b/src/corelib/kernel/qjni_p.h
@@ -0,0 +1,264 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#ifndef QJNI_P_H
+#define QJNI_P_H
+
+#include <jni.h>
+#include <QtCore/qglobal.h>
+#include <QtCore/qsharedpointer.h>
+
+QT_BEGIN_NAMESPACE
+
+class Q_CORE_EXPORT QJNIEnvironmentPrivate
+{
+public:
+    QJNIEnvironmentPrivate();
+    ~QJNIEnvironmentPrivate();
+    JNIEnv *operator->();
+    operator JNIEnv*() const;
+
+private:
+    friend class QJNIEnvironment;
+    Q_DISABLE_COPY(QJNIEnvironmentPrivate)
+    JNIEnv *jniEnv;
+};
+
+class Q_CORE_EXPORT QJNIObjectData
+{
+public:
+    QJNIObjectData();
+    ~QJNIObjectData();
+    jobject m_jobject;
+    jclass m_jclass;
+    bool m_own_jclass;
+};
+
+class Q_CORE_EXPORT QJNIObjectPrivate
+{
+public:
+    QJNIObjectPrivate();
+    explicit QJNIObjectPrivate(const char *className);
+    QJNIObjectPrivate(const char *className, const char *sig, ...);
+    explicit QJNIObjectPrivate(jclass clazz);
+    QJNIObjectPrivate(jclass clazz, const char *sig, ...);
+    QJNIObjectPrivate(jobject obj);
+
+    template <typename T>
+    T callMethod(const char *methodName,
+                 const char *sig,
+                 ...) const;
+    template <typename T>
+    T callMethod(const char *methodName) const;
+    template <typename T>
+    QJNIObjectPrivate callObjectMethod(const char *methodName) const;
+    QJNIObjectPrivate callObjectMethod(const char *methodName,
+                                       const char *sig,
+                                       ...) const;
+    template <typename T>
+    static T callStaticMethod(const char *className,
+                              const char *methodName,
+                              const char *sig, ...);
+    template <typename T>
+    static T callStaticMethod(const char *className,
+                              const char *methodName);
+    template <typename T>
+    static T callStaticMethod(jclass clazz,
+                              const char *methodName,
+                              const char *sig, ...);
+    template <typename T>
+    static T callStaticMethod(jclass clazz,
+                              const char *methodName);
+    static QJNIObjectPrivate callStaticObjectMethod(const char *className,
+                                             const char *methodName,
+                                             const char *sig, ...);
+
+    static QJNIObjectPrivate callStaticObjectMethod(jclass clazz,
+                                             const char *methodName,
+                                             const char *sig, ...);
+
+    template <typename T>
+    T getField(const char *fieldName) const;
+    template <typename T>
+    static T getStaticField(const char *className, const char *fieldName);
+    template <typename T>
+    static T getStaticField(jclass clazz, const char *fieldName);
+
+    QJNIObjectPrivate getObjectField(const char *fieldName, const char *sig) const;
+    static QJNIObjectPrivate getStaticObjectField(const char *className,
+                                                  const char *fieldName,
+                                                  const char *sig);
+    static QJNIObjectPrivate getStaticObjectField(jclass clazz,
+                                                  const char *fieldName,
+                                                  const char *sig);
+
+    template <typename T>
+    void setField(const char *fieldName, T value);
+    template <typename T>
+    void setField(const char *fieldName, const char *sig, T value);
+    template <typename T>
+    static void setStaticField(const char *className,
+                               const char *fieldName,
+                               T value);
+    template <typename T>
+    static void setStaticField(const char *className,
+                               const char *fieldName,
+                               const char *sig,
+                               T value);
+    template <typename T>
+    static void setStaticField(jclass clazz,
+                               const char *fieldName,
+                               const char *sig,
+                               T value);
+
+    template <typename T>
+    static void setStaticField(jclass clazz,
+                               const char *fieldName,
+                               T value);
+
+    static QJNIObjectPrivate fromString(const QString &string);
+    QString toString() const;
+
+    static bool isClassAvailable(const char *className);
+    bool isValid() const;
+    jobject object() const { return d->m_jobject; }
+
+    template <typename T>
+    inline QJNIObjectPrivate &operator=(T o)
+    {
+        jobject jobj = static_cast<jobject>(o);
+        if (!isSameObject(jobj)) {
+            d = QSharedPointer<QJNIObjectData>(new QJNIObjectData());
+            QJNIEnvironmentPrivate env;
+            d->m_jobject = env->NewGlobalRef(jobj);
+            d->m_jclass = static_cast<jclass>(env->NewGlobalRef(env->GetObjectClass(jobj)));
+        }
+
+        return *this;
+    }
+
+private:
+    friend class QJNIObject;
+
+    template <typename T>
+    T callMethod(const char *methodName,
+                 const char *sig,
+                 va_list args) const;
+    QJNIObjectPrivate callObjectMethod(const char *methodName,
+                                       const char *sig,
+                                       va_list args) const;
+    template <typename T>
+    static T callStaticMethod(const char *className,
+                              const char *methodName,
+                              const char *sig, va_list args);
+    template <typename T>
+    static T callStaticMethod(jclass clazz,
+                              const char *methodName,
+                              const char *sig, va_list args);
+    static QJNIObjectPrivate callStaticObjectMethod(const char *className,
+                                                    const char *methodName,
+                                                    const char *sig, va_list args);
+
+    static QJNIObjectPrivate callStaticObjectMethod(jclass clazz,
+                                                    const char *methodName,
+                                                    const char *sig, va_list args);
+
+    bool isSameObject(jobject obj) const;
+    bool isSameObject(const QJNIObjectPrivate &other) const;
+
+    friend bool operator==(const QJNIObjectPrivate &, const QJNIObjectPrivate &);
+    friend bool operator!=(const QJNIObjectPrivate&, const QJNIObjectPrivate&);
+    template <typename T> friend bool operator!=(const QJNIObjectPrivate&, T);
+    template <typename T> friend bool operator==(const QJNIObjectPrivate&, T);
+    template <typename T> friend bool operator!=(T, const QJNIObjectPrivate&);
+    template <typename T> friend bool operator==(T, const QJNIObjectPrivate&);
+
+    QSharedPointer<QJNIObjectData> d;
+};
+
+inline bool operator==(const QJNIObjectPrivate&obj1, const QJNIObjectPrivate&obj2)
+{
+    return obj1.isSameObject(obj2);
+}
+
+inline bool operator!=(const QJNIObjectPrivate&obj1, const QJNIObjectPrivate&obj2)
+{
+    return !obj1.isSameObject(obj2);
+}
+
+template <typename T>
+inline bool operator==(const QJNIObjectPrivate &obj1, T obj2)
+{
+    return obj1.isSameObject(static_cast<jobject>(obj2));
+}
+
+template <typename T>
+inline bool operator==(T obj1, const QJNIObjectPrivate &obj2)
+{
+    return obj2.isSameObject(static_cast<jobject>(obj1));
+}
+
+template <typename T>
+inline bool operator!=(const QJNIObjectPrivate &obj1, T obj2)
+{
+    return !obj1.isSameObject(obj2);
+}
+
+template <typename T>
+inline bool operator!=(T obj1, const QJNIObjectPrivate &obj2)
+{
+    return !obj2.isSameObject(obj1);
+}
+
+QT_END_NAMESPACE
+
+#endif // QJNI_P_H