diff --git a/coreapi/friend.c b/coreapi/friend.c
index c8417e22c..1a9705ea3 100644
--- a/coreapi/friend.c
+++ b/coreapi/friend.c
@@ -656,3 +656,7 @@ void linphone_core_write_friends_config(LinphoneCore* lc)
 	linphone_friend_write_to_config_file(lc->config,NULL,i);	/* set the end */
 }
 
+LinphoneCore *linphone_friend_get_core(const LinphoneFriend *fr){
+	return fr->lc;
+}
+
diff --git a/coreapi/linphonecore_jni.cc b/coreapi/linphonecore_jni.cc
index a1f428b4a..5839f0c4b 100644
--- a/coreapi/linphonecore_jni.cc
+++ b/coreapi/linphonecore_jni.cc
@@ -2222,6 +2222,16 @@ extern "C" jint Java_org_linphone_core_LinphoneFriendImpl_getStatus(JNIEnv*  env
 																		,jlong ptr) {
 	return (jint)linphone_friend_get_status((LinphoneFriend*)ptr);
 }
+extern "C" jobject Java_org_linphone_core_LinphoneFriendImpl_getCore(JNIEnv*  env
+																		,jobject  thiz
+																		,jlong ptr) {
+	LinphoneCore *lc=linphone_friend_get_core((LinphoneFriend*)ptr);
+	if (lc!=NULL){
+		LinphoneCoreData* lcData = (LinphoneCoreData*)linphone_core_get_user_data(lc);
+		return lcData->core;
+	}
+	return NULL;
+}
 
 /*
  * Class:     org_linphone_core_LinphoneFriendImpl
diff --git a/coreapi/linphonefriend.h b/coreapi/linphonefriend.h
index 66fbcea8e..a38db19d0 100644
--- a/coreapi/linphonefriend.h
+++ b/coreapi/linphonefriend.h
@@ -392,6 +392,11 @@ LINPHONE_PUBLIC LinphoneFriend *linphone_core_find_friend(const LinphoneCore *lc
  */
 LINPHONE_PUBLIC LinphoneFriend *linphone_core_get_friend_by_ref_key(const LinphoneCore *lc, const char *key);
 
+
+/**
+ * Returns the LinphoneCore object managing this friend, if any.
+ */
+LINPHONE_PUBLIC LinphoneCore *linphone_friend_get_core(const LinphoneFriend *fr);
 /**
  * @}
  */
diff --git a/java/impl/org/linphone/core/LinphoneFriendImpl.java b/java/impl/org/linphone/core/LinphoneFriendImpl.java
index 843170ce2..986f0a6b7 100644
--- a/java/impl/org/linphone/core/LinphoneFriendImpl.java
+++ b/java/impl/org/linphone/core/LinphoneFriendImpl.java
@@ -34,8 +34,9 @@ class LinphoneFriendImpl implements LinphoneFriend, Serializable {
 	private native void setPresenceModel(long nativePtr, long presencePtr);
 	private native void edit(long nativePtr);
 	private native void done(long nativePtr);
-	
 	private native void  delete(long ptr);
+	private native Object getCore(long ptr);
+	
 	boolean ownPtr = false;
 	protected LinphoneFriendImpl()  {
 		nativePtr = newLinphoneFriend(null);
@@ -57,13 +58,17 @@ class LinphoneFriendImpl implements LinphoneFriend, Serializable {
 		return new LinphoneAddressImpl(getAddress(nativePtr),LinphoneAddressImpl.WrapMode.FromConst);
 	}
 	public void setIncSubscribePolicy(SubscribePolicy policy) {
-		setIncSubscribePolicy(nativePtr,policy.mValue);
+		synchronized(getSyncObject()){
+			setIncSubscribePolicy(nativePtr,policy.mValue);
+		}
 	}
 	public SubscribePolicy getIncSubscribePolicy() {
 		return SubscribePolicy.fromInt(getIncSubscribePolicy(nativePtr)) ;
 	}
 	public void enableSubscribes(boolean enable) {
-		enableSubscribes(nativePtr, enable);
+		synchronized(getSyncObject()){
+			enableSubscribes(nativePtr, enable);
+		}
 	}
 	public boolean isSubscribesEnabled() {
 		return isSubscribesEnabled(nativePtr);
@@ -75,12 +80,27 @@ class LinphoneFriendImpl implements LinphoneFriend, Serializable {
 		return (PresenceModel)getPresenceModel(nativePtr);
 	}
 	public void edit() {
-		edit(nativePtr);
+		synchronized(getSyncObject()){
+			edit(nativePtr);
+		}
 	}
 	public void done() {
-		done(nativePtr);
+		synchronized(getSyncObject()){
+			done(nativePtr);
+		}
 	}
 	public long getNativePtr() {
 		return nativePtr;
 	}
+	
+	/*
+	 * Returns a java object to synchronize this friend with.
+	 * Indeed some operation must be synchronized with the LinphoneCore object.
+	 * If the friend is not associated with a LinphoneCore object, it returns itself in order to avoid writing code for case where no synchronization is necessary.
+	 */
+	private Object getSyncObject(){
+		Object core=getCore(nativePtr);
+		if (core!=null) return core;
+		else return this;
+	}
 }