Protect event handler from the exceptions

Change-Id: I8c7b68f4eff1460e02dd4cc01b7d655a5d7ad581
(cherry picked from commit 6bfdeb3215247561313a083d4131fc77d9c3792e)
diff --git a/core/net/src/main/java/org/onosproject/net/group/impl/GroupDriverProvider.java b/core/net/src/main/java/org/onosproject/net/group/impl/GroupDriverProvider.java
index 1092d8d..51f0420 100644
--- a/core/net/src/main/java/org/onosproject/net/group/impl/GroupDriverProvider.java
+++ b/core/net/src/main/java/org/onosproject/net/group/impl/GroupDriverProvider.java
@@ -130,8 +130,12 @@
     }
 
     private void pollDeviceGroups(DeviceId deviceId) {
-        Collection<Group> groups = getGroupProgrammable(deviceId).getGroups();
-        groupProviderService.pushGroupMetrics(deviceId, groups);
+        try {
+            Collection<Group> groups = getGroupProgrammable(deviceId).getGroups();
+            groupProviderService.pushGroupMetrics(deviceId, groups);
+        } catch (Exception e) {
+            log.warn("Exception thrown while polling groups from {}", deviceId, e);
+        }
     }
 
     private GroupProgrammable getGroupProgrammable(DeviceId deviceId) {