Fixed some sonar-reported issues.
diff --git a/net/api/src/main/java/org/onlab/onos/event/AbstractListenerRegistry.java b/net/api/src/main/java/org/onlab/onos/event/AbstractListenerRegistry.java
index 5e6011a..9710306 100644
--- a/net/api/src/main/java/org/onlab/onos/event/AbstractListenerRegistry.java
+++ b/net/api/src/main/java/org/onlab/onos/event/AbstractListenerRegistry.java
@@ -45,7 +45,7 @@
         for (L listener : listeners) {
             try {
                 listener.event(event);
-            } catch (Throwable error) {
+            } catch (Exception error) {
                 reportProblem(event, error);
             }
         }
diff --git a/net/core/trivial/src/main/java/org/onlab/onos/event/impl/SimpleEventDispatcher.java b/net/core/trivial/src/main/java/org/onlab/onos/event/impl/SimpleEventDispatcher.java
index da919e4..3834676 100644
--- a/net/core/trivial/src/main/java/org/onlab/onos/event/impl/SimpleEventDispatcher.java
+++ b/net/core/trivial/src/main/java/org/onlab/onos/event/impl/SimpleEventDispatcher.java
@@ -82,7 +82,7 @@
                         log.warn("No sink registered for event class {}",
                                  event.getClass());
                     }
-                } catch (Throwable e) {
+                } catch (Exception e) {
                     log.warn("Error encountered while dispatching event:", e);
                 }
             }
diff --git a/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java b/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java
index b713f00..9df00b0 100644
--- a/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java
+++ b/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java
@@ -141,7 +141,6 @@
         public void updatePorts(DeviceId deviceId, List<PortDescription> portDescriptions) {
             checkNotNull(deviceId, DEVICE_ID_NULL);
             checkNotNull(portDescriptions, "Port descriptions list cannot be null");
-            // FIXME: fix the interface to accept DeviceId separately
             log.info("Device {} ports updated: {}", portDescriptions);
             List<DeviceEvent> events = store.updatePorts(deviceId, portDescriptions);
             for (DeviceEvent event : events) {