diff --git a/app/src/main/java/fr/chteufleur/mytrackingdog/services/ServiceXmpp.java b/app/src/main/java/fr/chteufleur/mytrackingdog/services/ServiceXmpp.java
index 39fc09d..7cfa597 100644
--- a/app/src/main/java/fr/chteufleur/mytrackingdog/services/ServiceXmpp.java
+++ b/app/src/main/java/fr/chteufleur/mytrackingdog/services/ServiceXmpp.java
@@ -67,7 +67,6 @@ public class ServiceXmpp extends Observable implements PresenceEventListener {
     private AbstractXMPPConnection connection;
     private String jid;
     private String otherJid;
-    private Roster roster;
     private final ServiceXmpp thsi;
 
     private boolean isEnable = false;
@@ -100,7 +99,7 @@ public class ServiceXmpp extends Observable implements PresenceEventListener {
         connection.login();
 
         registerCommands();
-        roster = Roster.getInstanceFor(connection);
+        Roster roster = Roster.getInstanceFor(connection);
         roster.addPresenceEventListener(this);
 
         isConnected = connection.isConnected();
@@ -127,6 +126,7 @@ public class ServiceXmpp extends Observable implements PresenceEventListener {
             try {
                 sendPresenceUnavailable(otherJid);
             } catch (SmackException.NotConnectedException | InterruptedException | XmppStringprepException ex) {
+                ex.printStackTrace();
             }
         }
         if (connection != null) {
@@ -218,25 +218,25 @@ public class ServiceXmpp extends Observable implements PresenceEventListener {
     private void registerCommands() {
         commandManager.registerCommand(XMPP_NODE_TRAIL_GEOLOC, XMPP_NODE_TRAIL_GEOLOC, new LocalCommandFactory() {
             @Override
-            public LocalCommand getInstance() throws InstantiationException, IllegalAccessException {
+            public LocalCommand getInstance() {
                 return new TrailGeolocCommand(thsi);
             }
         });
         commandManager.registerCommand(XMPP_NODE_OBJECT_GEOLOC, XMPP_NODE_OBJECT_GEOLOC, new LocalCommandFactory() {
             @Override
-            public LocalCommand getInstance() throws InstantiationException, IllegalAccessException {
+            public LocalCommand getInstance() {
                 return new ObjectGeolocCommand(thsi);
             }
         });
         commandManager.registerCommand(XMPP_NODE_START_TRAIL_GEOLOC, XMPP_NODE_START_TRAIL_GEOLOC, new LocalCommandFactory() {
             @Override
-            public LocalCommand getInstance() throws InstantiationException, IllegalAccessException {
+            public LocalCommand getInstance() {
                 return new StartTrailGeolocCommand(thsi);
             }
         });
         commandManager.registerCommand(XMPP_NODE_STOP_TRAIL_GEOLOC, XMPP_NODE_STOP_TRAIL_GEOLOC, new LocalCommandFactory() {
             @Override
-            public LocalCommand getInstance() throws InstantiationException, IllegalAccessException {
+            public LocalCommand getInstance() {
                 return new StopTrailGeolocCommand(thsi);
             }
         });