Fixed Core references being held in different places in the app, preventing from being unref'ed at native level

app/src/main/java/org/linphone/LinphoneService.java

@@ -413,15 +413,23 @@ public final class LinphoneService extends Service {
             getApplication().unregisterActivityLifecycleCallbacks(mActivityCallbacks);
             mActivityCallbacks = null;
         }
-
         destroyOverlay();
+
         Core lc = LinphoneManager.getLcIfManagerNotDestroyedOrNull();
         if (lc != null) {
             lc.removeListener(mListener);
+            lc = null; // To allow the gc calls below to free the Core
         }
 
         sInstance = null;
         LinphoneManager.destroy();
+        // The following are required if we want for the Core's finalize() method to be called
+        // before the super.onDestroy() call.
+        // We have to so there are no more ref on the native LinphoneCore object and thus call
+        // it's uninit() method which will free the AndroidPlatformHelper resources...
+        // Problem is both the below methods do not guaranty the finalize will be called in time...
+        //System.gc();
+        //System.runFinalization();
 
         // Make sure our notification is gone.
         mNotificationManager.destroy();
@@ -432,7 +440,9 @@ public final class LinphoneService extends Service {
             LinphoneActivity.instance().finish();
         }
 
+        if (LinphonePreferences.instance().useJavaLogger()) {
             Factory.instance().getLoggingService().removeListener(mJavaLoggingService);
+        }
 
         super.onDestroy();
     }

app/src/main/java/org/linphone/contacts/ContactsManager.java

@@ -122,6 +122,20 @@ public class ContactsManager extends ContentObserver implements FriendListListen
     }
 
     public void destroy() {
+        if (mLoadContactTask != null) {
+            mLoadContactTask.cancel(true);
+        }
+        // LinphoneContact has a Friend field and Friend can have a LinphoneContact has userData
+        // Friend also keeps a ref on the Core, so we have to clean them
+        for (LinphoneContact c : mContacts) {
+            c.setFriend(null);
+        }
+        mContacts.clear();
+        for (LinphoneContact c : mSipContacts) {
+            c.setFriend(null);
+        }
+        mSipContacts.clear();
+
         Core lc = LinphoneManager.getLcIfManagerNotDestroyedOrNull();
         if (lc != null) {
             for (FriendList list : lc.getFriendsLists()) {

app/src/main/java/org/linphone/contacts/LinphoneContact.java

@@ -393,9 +393,14 @@ public class LinphoneContact extends AndroidContact
     }
 
     public void setFriend(Friend f) {
+        if (mFriend != null && (f == null || f != mFriend)) {
+            mFriend.setUserData(null);
+        }
         mFriend = f;
+        if (mFriend != null) {
             mFriend.setUserData(this);
         }
+    }
 
     public boolean isInFriendList() {
         if (mFriend == null) return false;

app/src/main/java/org/linphone/fragments/StatusFragment.java

@@ -112,7 +112,12 @@ public class StatusFragment extends Fragment {
                                     new OnClickListener() {
                                         @Override
                                         public void onClick(View v) {
-                                            lc.refreshRegisters();
+                                            Core core =
+                                                    LinphoneManager
+                                                            .getLcIfManagerNotDestroyedOrNull();
+                                            if (core != null) {
+                                                core.refreshRegisters();
+                                            }
                                         }
                                     });
                         } catch (IllegalStateException ise) {