diff --git a/wrappers/java/genwrapper.py b/wrappers/java/genwrapper.py
index 4d97f4573..2355d0042 100755
--- a/wrappers/java/genwrapper.py
+++ b/wrappers/java/genwrapper.py
@@ -78,6 +78,17 @@ ENUMS_LIST = {
     'XmlRpcRequestStatus': 'XmlRpcRequest',
 }
 
+CORE_ACCESSOR_LIST = [
+    'Call',
+    'ChatRoom',
+    'Event',
+    'Friend',
+    'FriendList',
+    'NatPolicy',
+    'Player',
+    'ProxyConfig'
+]
+
 ##########################################################################
 
 class JavaTranslator(object):
@@ -271,12 +282,12 @@ class JavaTranslator(object):
     def translate_argument(self, _arg, native=False, jni=False):
         return '{0} {1}'.format(self.translate_type(_arg.type, native, jni), self.translate_argument_name(_arg.name))
 
-    def translate_property(self, _property):
+    def translate_property(self, _property, _hasCoreAccessor):
         properties = []
         if _property.getter is not None:
-            properties.append(self.translate_method(_property.getter))
+            properties.append(self.translate_method(_property.getter, _hasCoreAccessor))
         if _property.setter is not None:
-            properties.append(self.translate_method(_property.setter))
+            properties.append(self.translate_method(_property.setter, _hasCoreAccessor))
         return properties
 
     def translate_jni_property(self, className, _property):
@@ -317,7 +328,7 @@ class JavaTranslator(object):
     def generate_set_listener(self, _class):
         return self.generate_listener('setListener', _class)
 
-    def translate_method(self, _method):
+    def translate_method(self, _method, _hasCoreAccessor=False):
         methodDict = {}
 
         methodDict['return'] = self.translate_type(_method.returnType, isReturn=True)
@@ -328,6 +339,8 @@ class JavaTranslator(object):
         methodDict['convertInputClassArrayToLongArray'] = False
 
         methodDict['name'] = _method.name.to_camel_case(lower=True)
+        methodDict['isNotGetCore'] = not methodDict['name'] == 'getCore'
+        methodDict['hasCoreAccessor'] = _hasCoreAccessor
         methodDict['exception'] = self.throws_exception(_method.returnType)
 
         methodDict['enumCast'] = type(_method.returnType) is AbsApi.EnumType
@@ -459,16 +472,17 @@ class JavaTranslator(object):
         classDict['isLinphoneCore'] = _class.name.to_camel_case() == "Core"
         classDict['doc'] = _class.briefDescription.translate(self.docTranslator) if _class.briefDescription is not None else None
 
+        hasCoreAccessor = _class.name.to_camel_case() in CORE_ACCESSOR_LIST
         for _property in _class.properties:
             try:
-                classDict['methods'] += self.translate_property(_property)
+                classDict['methods'] += self.translate_property(_property, hasCoreAccessor)
                 classDict['jniMethods'] += self.translate_jni_property(_class.name, _property)
             except AbsApi.Error as e:
                 logging.error('error while translating {0} property: {1}'.format(_property.name.to_snake_case(), e.args[0]))
 
         for method in _class.instanceMethods:
             try:
-                methodDict = self.translate_method(method)
+                methodDict = self.translate_method(method, hasCoreAccessor)
                 jniMethodDict = self.translate_jni_method(_class.name, method)
                 classDict['methods'].append(methodDict)
                 classDict['jniMethods'].append(jniMethodDict)
@@ -477,7 +491,7 @@ class JavaTranslator(object):
 
         for method in _class.classMethods:
             try:
-                methodDict = self.translate_method(method)
+                methodDict = self.translate_method(method, hasCoreAccessor)
                 jniMethodDict = self.translate_jni_method(_class.name, method, True)
                 classDict['methods'].append(methodDict)
                 classDict['jniMethods'].append(jniMethodDict)
diff --git a/wrappers/java/java_class.mustache b/wrappers/java/java_class.mustache
index 81a8fd9e6..3d11715d9 100644
--- a/wrappers/java/java_class.mustache
+++ b/wrappers/java/java_class.mustache
@@ -181,9 +181,11 @@ class {{classImplName}} {{#isLinphoneFactory}}extends{{/isLinphoneFactory}}{{#is
 {{#methods}}
     private native {{return_native}} {{name}}({{native_params}});
     @Override
-    public {{return}} {{name}}({{params}}) {{#exception}}throws CoreException{{/exception}} {
+    synchronized public {{return}} {{name}}({{params}}) {{#exception}}throws CoreException{{/exception}} {
+        {{#hasCoreAccessor}}{{#isNotGetCore}}synchronized(getCore()) { {{/isNotGetCore}}{{/hasCoreAccessor}}
         {{#exception}}int exceptionResult = {{/exception}}{{return_keyword}}{{#enumCast}}{{return}}.fromInt({{/enumCast}}{{#classCast}}({{return}}){{/classCast}}{{name}}(nativePtr{{native_params_impl}}){{#enumCast}}){{/enumCast}};{{#exception}}
-        if (exceptionResult != 0) throw new CoreException("{{name}} returned value " + exceptionResult);{{/exception}}
+        if (exceptionResult != 0) throw new CoreException("{{name}} returned value " + exceptionResult);{{/exception}}{{#hasCoreAccessor}}{{#isNotGetCore}} 
+        }{{/isNotGetCore}}{{/hasCoreAccessor}}
     }
 
 {{/methods}}
diff --git a/wrappers/java/jni.mustache b/wrappers/java/jni.mustache
index f0ad0e6c4..7481796f2 100644
--- a/wrappers/java/jni.mustache
+++ b/wrappers/java/jni.mustache
@@ -220,6 +220,7 @@ public:
 };
 
 //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -298,7 +299,7 @@ static {{return}} {{callbackName}}({{params}}) {
 	jobject jlistener = (jobject) {{cPrefix}}_cbs_get_user_data(cbs);
 
 	if (jlistener == NULL) {
-		ms_warning("{{name}}() notification without listener");
+		ms_warning("{{callbackName}}() notification without listener");
 		return{{returnIfFail}};
 	}
 
@@ -403,8 +404,6 @@ jobject Java_{{jni_package}}CoreImpl_getMediastreamerFactory(JNIEnv *env, jobjec
 
 jobject Java_{{jni_package}}FactoryImpl_createCore(JNIEnv *env, jobject thiz, jobject jfactory, jobject jlistener, jstring jconfig_path, jstring jfactory_config_path, jobject jcontext) {
 	LinphoneFactory *cptr = linphone_factory_get();
-	SetObjectNativePtr(env, jfactory, (jlong)cptr); // Set the C factory ptr as Factory.nativePtr for next factory calls
-
 	LinphoneCoreCbs *cbs = linphone_factory_create_core_cbs(cptr);
 	jobject listener = env->NewGlobalRef(jlistener);