diff --git a/wrappers/java/genwrapper.py b/wrappers/java/genwrapper.py
index 9a4d28949..51465d7da 100644
--- a/wrappers/java/genwrapper.py
+++ b/wrappers/java/genwrapper.py
@@ -483,9 +483,19 @@ class JavaTranslator(object):
         methodDict['callbackName'] = methodDict['cPrefix'] + '_' + _method.name.to_snake_case()
         methodDict['jname'] = _method.name.to_camel_case(lower=True)
         methodDict['return'] = self.translate_as_c_base_type(_method.returnType)
+        methodDict['jniUpcallMethod'] = 'CallVoidMethod'
+        methodDict['isJniUpcallBasicType'] = False
+        methodDict['isJniUpcallObject'] = False
         if type(_method.returnType) is AbsApi.ClassType:
             methodDict['return'] += '*'
-        methodDict['returnIfFail'] = '' if  methodDict['return'] == 'void' else ' NULL' #TODO
+            methodDict['jniUpcallMethod'] = 'CallObjectMethod'
+            methodDict['isJniUpcallObject'] = True
+            methodDict['jniUpcallType'] = 'jobject'
+        elif type(_method.returnType) is AbsApi.BaseType:
+            methodDict['jniUpcallMethod'] = 'CallIntMethod'
+            methodDict['jniUpcallType'] = self.translate_type(_method.returnType, jni=True)
+            methodDict['isJniUpcallBasicType'] = True
+        methodDict['returnIfFail'] = '' if  methodDict['return'] == 'void' else ' NULL'
         methodDict['hasReturn'] = not methodDict['return'] == 'void'
         methodDict['isSingleListener'] = not _class.multilistener
         methodDict['isMultiListener'] = _class.multilistener
@@ -531,7 +541,12 @@ class JavaTranslator(object):
         if (methodDict['return'] == 'void'):
             methodDict['jparams'] += 'V'
         else:
-            pass #TODO
+            if type(_method.returnType) is AbsApi.ClassType:
+                methodDict['jparams'] += 'L' + self.jni_path + _method.returnType.desc.name.to_camel_case() + ';'
+            elif type(_method.returnType) is AbsApi.BaseType:
+                methodDict['jparams'] += self.translate_java_jni_base_type_name(_method.returnType.name)
+            else:
+                pass #TODO
 
         return methodDict
 
diff --git a/wrappers/java/jni.mustache b/wrappers/java/jni.mustache
index 607f7af64..bb45e503d 100644
--- a/wrappers/java/jni.mustache
+++ b/wrappers/java/jni.mustache
@@ -210,7 +210,16 @@ static {{return}} {{callbackName}}({{params}}) {
 	jstring j_{{stringName}} = {{stringName}} ? env->NewStringUTF({{stringName}}) : NULL;
 	{{/jstrings}}
 	
-	env->CallVoidMethod(jlistener, jcallback, {{params_impl}});
+	{{#hasReturn}}{{jniUpcallType}} jni_upcall_result = {{/hasReturn}}env->{{jniUpcallMethod}}(jlistener, jcallback, {{params_impl}});
+	{{#hasReturn}}
+	{{#isJniUpcallObject}}
+	{{return}} c_upcall_result = NULL;
+	if (jni_upcall_result) c_upcall_result = ({{return}})GetObjectNativePtr(env, jni_upcall_result);
+	{{/isJniUpcallObject}}
+	{{#isJniUpcallBasicType}}
+	{{return}} c_upcall_result = ({{return}}) jni_upcall_result;
+	{{/isJniUpcallBasicType}}
+	{{/hasReturn}}
 
 	{{#jobjects}}
 	if (j_{{objectName}}) {
@@ -225,7 +234,7 @@ static {{return}} {{callbackName}}({{params}}) {
 
 	handle_possible_java_exception(env, jlistener);
 	{{#hasReturn}}
-	return 0;
+	return c_upcall_result;
 	{{/hasReturn}}
 }
 
diff --git a/wrappers/java/migration.sh b/wrappers/java/migration.sh
index 106156d2c..3d826c470 100644
--- a/wrappers/java/migration.sh
+++ b/wrappers/java/migration.sh
@@ -304,13 +304,10 @@ eval "$SED_START 's/linkPhoneNumberWithAccount()/linkAccount()/g' $SED_END"
 eval "$SED_START 's/zoomVideo(/zoom(/g' $SED_END"
 eval "$SED_START 's/mLc.setCpuCount(/\/\/mLc.setCpuCount(/g' $SED_END"
 
-#Core.setCpuCount() => Not needed anymore, can be removed
 # TODO
 #Tunnel, TunnelConfig
-#LinphoneBuffer
 #AccountCreator.updatePassword => What to do ?
 # XmlRpcRequest and XmlRpcSession constructors
-# Callbacks with return like chat messages' file transfer
 
 #Android specifics not wrapped automatically
 #Core.startEchoCalibration
@@ -337,6 +334,8 @@ eval "$SED_START 's/mLc.setCpuCount(/\/\/mLc.setCpuCount(/g' $SED_END"
 # setPrimaryContact only takes one String argument
 # AdaptiveRateAlgorithm was an enum, now is nothing
 # createAddress(userName,domain,null); no longer exists
+# Buffer.setContent now takes the size as second parameter
+# ChatMessageListener onFileTransferSend now returns the Buffer instead of having it as part of his arguments
 
 # # Factory
 #Factory.createLpConfigFromString => Config.newFromBuffer