Fixing various issues and re-tuning.

Change-Id: I8822fcf77cfa507788241c5bda98ef4741b284b4
diff --git a/core/api/src/main/java/org/onlab/onos/event/AbstractEventAccumulator.java b/core/api/src/main/java/org/onlab/onos/event/AbstractEventAccumulator.java
index f866633..39c1103 100644
--- a/core/api/src/main/java/org/onlab/onos/event/AbstractEventAccumulator.java
+++ b/core/api/src/main/java/org/onlab/onos/event/AbstractEventAccumulator.java
@@ -16,6 +16,8 @@
 package org.onlab.onos.event;
 
 import com.google.common.collect.Lists;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.List;
 import java.util.Timer;
@@ -31,6 +33,8 @@
  */
 public abstract class AbstractEventAccumulator implements EventAccumulator {
 
+    private Logger log = LoggerFactory.getLogger(AbstractEventAccumulator.class);
+
     private final Timer timer;
     private final int maxEvents;
     private final int maxBatchMillis;
@@ -104,9 +108,13 @@
     private class ProcessorTask extends TimerTask {
         @Override
         public void run() {
-            idleTask = cancelIfActive(idleTask);
-            maxTask = cancelIfActive(maxTask);
-            processEvents(finalizeCurrentBatch());
+            try {
+                idleTask = cancelIfActive(idleTask);
+                maxTask = cancelIfActive(maxTask);
+                processEvents(finalizeCurrentBatch());
+            } catch (Exception e) {
+                log.warn("Unable to process batch due to {}", e.getMessage());
+            }
         }
     }